This has been one of the most eventful years since I began covering global security for the BBC in the aftermath of the 11 September attacks in 2001.

The sudden toppling of Syria's President Assad, North Korean soldiers fighting for Russia. British and US missiles sent to Ukraine and fired at Russia, Iranian missiles shipped to Russia. US-armed Israeli air strikes in Lebanon and Gaza, Yemeni missiles fired at Israel.

It's a complex and confusing web of conflicts and it prompts the inevitable question: Are the world's battle lines becoming ever more interconnected?

Let's get one thing straight: this is not World War Three, although President Putin does like to dangle that menace to scare the West away from sending more powerful weapons to Ukraine. But it's clear that many of the conflicts on our planet have an international dimension, so how do these lines join up?

We can start with the war that has been raging in the east of Europe, across Ukraine since 24 February 2022 when Russia launched its full-scale invasion of Ukraine in a failed bid to take over the whole country.

'They are not completely aware that they are coming here to die. It will be a huge surprise for them'. Rustam Nugudin, "Achilles" Battalion, Ukrainian Armed Forces

Lurid media reports that inexperienced North Korean troops, newly arrived on the battlefield, are "gorging" on internet porn, something unavailable to them in their own closed, hermit state, can not mask the fact that their involvement in this European war is a serious escalation. Serious enough to prompt the US and other Western countries to lift their ban on Ukraine using Western long-range missiles to attack targets deep inside Russia, provoking fury in the Kremlin.

Beyond the battlefield bravado, the arrival of a division-sized contingent of North Korean soldiers, thought to number between 10-12,000, is bad news for Ukraine which is already struggling with a shortage of manpower.

"Even if they are not the strongest soldiers, 10,000 is quite a lot, it's two brigades", says Rustam Nugudin, a Ukrainian commander on the frontline. "Just imagine that it only took two brigades to push the Russians back from the Kharkiv region."

Voicing a complaint shared by many Ukrainians, he adds: "Yes, our Western allies help us with some weapons and training, and we are very grateful for that, but the scale of it is incomparable next to the military assistance Russia gets from Iran and North Korea. It must be the other way round if you'd really like to see us – and Europe – win."

But the war in Ukraine was already internationalised long before the North Koreans showed up. Belarus, a nominally independent European nation but now almost completely in-step with Moscow, was used as a launch pad to attack Ukraine. From early on in the months following its 2022 invasion, Iran has been supplying Russia with Shahed explosive-tipped drones and more recently the Islamic Republic has been accused of shipping powerful ballistic missiles to Russia across the Caspian Sea.

And the West has hardly been a bystander in this conflict. A massive one-way pipeline of US, Nato and EU assistance, both financial and military, has enabled Ukraine to largely hold off the Russian army – until now.

"What we are seeing is a fundamental imbalance of approaches," says the BBC's Ukraine expert Vitaly Shevchenko. "While the West's policy of caution and containment has imposed limitations on what Ukraine can do, Moscow appears unconcerned about the conflict expanding and possibly even keen for it to do so."

The complexities of this region frankly make the Ukraine war look straightforward. Because there are several conflicts in this region all either raging or dormant, and all going on at the same time.

But first, an important caveat. Contrary to the impression we often get via the world's media, most of the Middle East is not at war. Day-to-day life in places like Dubai, Saudi Arabia and Egypt goes on as normal, untouched by the threat of war. Even in countries that have recently experienced conflict in some form, like Iraq and Iran, life is largely peaceful for most people.

Almost no one saw this one coming. Not Syria's now-departed President Bashar al-Assad. Nor his backers in Tehran, Moscow and South Beirut. Nor, it seems, America's multi-billion dollar intelligence community.

In the space of less than a fortnight, a coalition of Islamist rebels known as Hayat Tahrir al-Sham (HTS), who are designated as a terrorist organisation by the UN, US, EU and UK, managed to break out of their stronghold in northwest Syria and seize city after city until they have now become Syria's new rulers.

This is so much more than just a localised, single-country event; it has several international strands to it.

One of the many effects of the Hamas-led raid into southern Israel is that the Israeli government's response has had a devastating effect on Iran's allies in the region. The last time Syria's rebels looked like threatening Assad's rule, in 2015, Iran, Hezbollah and Russia all came to his aid and drove the rebels back. Not this time. Russia is busy fighting Ukraine, Hezbollah has been decimated by its short war with Israel and Iran is bruised after seeing how easily Israeli warplanes were able to penetrate its airspace in the autumn.

The net result is that Assad's allies were either incapable or unwilling to come to his aid, while Turkey, which backs the rebels, saw an opportunity to reshape the situation to its own advantage.

The situation in Gaza is nothing short of tragic.

The latest conflict there (and there have been many shorter ones before this one) was triggered by the raid led by Hamas (the militants proscribed as a terrorist group by many governments) into southern Israel on 7 October 2023 in which more than 1100 people were killed and around 250 taken into Gaza as hostages. Since then, Israel's war on Hamas has resulted in more than 44,000 Palestinians being killed there. These are mostly civilian deaths and although that figure comes from the Hamas-run Health Ministry, it is largely endorsed by independent aid agencies. Israel says it has largely degraded Hamas's military capabilities.

Today, 15 months into this war, much of Gaza lies in ruins. More than a million people have been displaced, often multiple times, out of a population of 2.4 million. Many of those are living in miserable conditions in tents, plagued by snakes, scorpions and scabies in the summer, and battered by the weather in the winter.

Numerous attempts to broker a ceasefire between Israel and Hamas have failed, despite the efforts of Qatar, Egypt, the US and others. Israel has vowed to eradicate Hamas as a military force and while its ranks have been heavily depleted, the fighting is not yet over and devastating Israeli airstrikes on built-up areas continue.

There appears to be no agreed plan for what happens after the fighting stops, nor who will govern the Gaza Strip after more than 18 years of rule by Hamas.

In many ways Gaza is the well-spring of other conflicts in the region, leading to exchanges of fire between Israel and, variously, Lebanon, Yemen, Iran and Syria.

Iran supports a number of allied or "proxy" militias around the Middle East, giving them money, weapons and training through its Quds Force, a branch of the Iran Revolutionary Guards Corps (IRGC). All are avowedly hostile to Israel and collectively known by Iran as the "Axis of Resistance".

In Lebanon, for years now, the strongest military force has not been the national army, nor the UN peacekeepers stationed in the south. It is Hezbollah, a militant force armed by Iran with advanced missiles and rockets.

On 8 October 2023, Hezbollah began raining rockets and drones down on northern Israel in solidarity, it said, with its brothers-in-arms in Gaza. In September 2024, Israel changed its war aims to include clearing Hezbollah away from the border so that more than 60,000 Israelis could return to their homes in the north.

Israel, through a combination of covert sabotage by Mossad, its external spy agency, and its military, the Israel Defence Forces (IDF), has dealt Hezbollah a series of devastating blows, assassinating its long-time leader, blowing up its communications and destroying tonnes of its weaponry. Thousands of people have been killed in the short Israel-Lebanon war that preceded a ceasefire in late November.

Israel is at war with Hamas in Gaza, Hezbollah in Lebanon and has fired missiles at – and been attacked from – Iran, Yemen, Syria and Iraq.

The US has continued to supply Israel with a colossal amount of military aid – both defensive such as the THAAD missile defence and offensive weapons such as parts for the F35 aircraft – despite the killing of so many Palestinians in Gaza and almost universal worldwide opprobrium. This makes the US – and by extension the West in general - unpopular in the Arab world and increases the risk of recruitment by proscribed terror groups likes Islamic State (IS) and Al-Qaida leading to what Western security officials say is the risk of a rise of transnational terrorism.

Iran's so-called "Axis of Resistance" – Hezbollah, Hamas, the Houthis etc – has been weakened by Israeli assaults this year but is not broken.

Iran, in addition to supplying its proxies in the region, has been sending missiles to Russia to be used against Ukraine. There are reports that in return Russian satellite intelligence is being passed to the Houthis in Yemen, via Iran, to help them target Western shipping passing from the Indian Ocean into the Red Sea.

Russia may have lost its key Mediterranean ally, Syria, but it still has a big one in the form of Libya's "Marshal" Khalifa Haftar in Benghazi. Russian air force cargo planes have recently been seen flying into Libyan airstrips, both on the coast and inland at a place called Brak. Moscow clearly sees Libya as both a springboard for projecting its global reach in the Mediterranean and also as a staging post for its mercenary activities further south in Sudan and the Sahel.

The Russian mercenary group formerly known as Wagner and now rebranded as "Afrika Korps" have successfully supplanted French and other Western forces in the Sahel nations and former French colonies of Mali, Burkina Faso, Niger and Central African Republic.

This means Russia has effectively inherited the IS jihadist problem in those countries but in the meantime it is enriching itself from lucrative deals that see mineral and other wealth flowing back to Moscow.

Ukraine recently appeared to take a wrong turn in this area by enabling a major attack on Malian government forces and their Russian mentors in July. Ukrainian Special Forces reportedly supplied drones and training to Tuareg rebels that resulted in an ambush, killing 84 Russian mercenaries and 47 Malian soldiers. Kyiv is clearly trying to "take the fight to the enemy" but if they were responsible for supplying the drones, this move is widely considered to have backfired. Ukraine has denied involvement.

South Korea is worried. There is no such thing as a free lunch, the saying goes, and Seoul is now wondering just what Pyongyang will be getting from Moscow in return for the dispatching all those thousands of North Korean soldiers to Russia's war effort in Ukraine. Will it be missile technology? Nuclear know-how? Submarine or satellite assistance?

Up until now South Korea has carefully avoided sending any military kit directly to Ukraine, sending it instead to the US to replace kit which then gets sent to Ukraine. But South Korea, which has an advanced military industrial base, is now considering lifting this ban and sending equipment directly to Kyiv.

All of this increases the already febrile tensions on the Korean Peninsula where a paranoid nuclear-armed state (the North) faces off against its pro-Western democratic neighbour (the South). The two countries never officially ended their war - it stopped with an Armistice in 1953.

This is not yet a conflict but it is a major potential flashpoint.

While the West spent the first 20 years of this century preoccupied with fighting insurgencies in Iraq and Afghanistan, China quietly colonised strategic reefs in international waters in the South China Sea and claimed them for its own. Its coastguard has since clashed frequently with Philippines vessels, claiming they are infringing on Chinese territory, despite being only just outside the Philippines maritime boundary and nowhere near China's coastline.

But the big worry is Taiwan. Beijing has repeatedly vowed to "return" this self-governing democracy to the mainland, even though it has never been ruled by Beijing at any point since the Communists came to power and the People's Republic of China came into being in 1949. President Xi Jinping has said publicly that this will be achieved, "by force if necessary" before the centenary of the Chinese Communist Party (CCP) in 2049.

Taiwan does not want to be ruled by the Chinese Communist Party in Beijing. It has voted in a pro-democracy, anti-Beijing president, William Lai, whom the politburo in Beijing absolutely detests. They accuse him of seeking independence for Taiwan (a red line for China) and responded to a recent robust speech of his with a series of threatening military exercises and air incursions all around the island.

The big question is: if China invades – or more likely blockades – Taiwan then will the US come to its defence by committing its own forces? Will a second-term President Trump view this as a challenge to America's vital interests in the Pacific? Or will he abandon Taiwan to its fate?

This has the potential for a truly catastrophic conflict with global economic consequences that would dwarf Russia's full-scale invasion of Ukraine.

This was the year that the balance of power in the Middle East shifted dramatically, in Israel's favour and to Iran's disadvantage. Israel's government has clearly decided to go all-out to "neutralise" its enemies, be they in Gaza, Lebanon, Yemen or Syria. Red lines previously adhered to, by both Iran and Israel, have now been crossed, with the two sides trading missiles in direct attacks on each other for the first time.

The Ukraine war has now shown itself to be almost certainly unwinnable, at least for Ukraine. Russia has ramped up its defence industrial machine to the extent it can now partially overwhelm Ukraine's air defences and its front lines but not so much that it can take the whole country. Yet Ukraine's position now looks weaker than at any time since the early months of the full-scale invasion.

The war has become increasingly internationalised, with North Korean troops arriving in Europe to fight on Russia's side and the West giving the green light for Ukraine to fire its long-range missiles into Russia.

Sweden has now joined Nato, meaning that eight Nato countries now border the Baltic Sea where Russia maintains two strategic footholds, in St Petersburg and Kaliningrad. There have been several incidents of so-called "hybrid warfare" in the Baltic, where Russia is suspected of purposefully damaging undersea communications cables.

There will likely be a concerted effort by the incoming Trump administration to force a peace deal in Ukraine. This may well stumble at the first hurdle. President Putin has already made his terms clear and they amount to virtual capitulation for Kyiv so will be largely unacceptable there, even for Ukraine's exhausted population. But if Trump turns off the tap of US weaponry then Europe cannot possibly make up the shortfall, leaving Ukraine weaker and even more prone to Russian attacks in the air and on the ground. Some kind of messy ceasefire deal may be the least painful of all options for Ukraine, even though it does not trust Putin's word.

The Middle East is still in flux. Iran and Israel have unfinished business but Tehran is well aware of its own weaknesses and of Israel's increasingly aggressive posture in the region. It would not take much provocation to trigger a new round of Israeli airstrikes on Iran. There is already widespread speculation that Donald Trump – who authorised the assassination of the Iranian Revolutionary Guards Quds Force Commander in 2020 – may work with Israel to attack Iran's nuclear programme.

Syria could go either way. It could settle down into a successful, pluralistic nation, bucking the trend of other revolutions in the region. Or it could descend into factional infighting. The West will continue to struggle to restrain Turkey from hitting the Syrian Kurds, the West's chief ally against IS.

Despite the global coalition against IS drawing down its military component in the Middle East, IS-KP (Islamic State Khorasan Province) showed how dangerous they are this year with the Moscow Crocus Hall attack that killed 145 people. Western intelligence estimates are that IS continues to try to capitalise on anger over Gaza and recruit volunteers for attacks in Europe including the UK.

There will be renewed pressure from all sides for a substantive peace deal in Gaza that brings the hostages home and ends Israel's assault on that battered territory. But Israel is reluctant to withdraw completely from the territory while Hamas, which holds the hostages, has always insisted this has to happen.

There is talk of a grand bargain that sees Saudi Arabia finally recognise the state of Israel in exchange for a binding security deal with Washington. But the Saudis have made clear this can only happen if there is a "clear, irrevocable path to an independent Palestinian state". That is something that Israel's PM Benjamin Netanyahu is vehemently opposed to and Israeli settlers seizing of Palestinian land continues apace and with President Trump in the White House its likely to continue further.

His re-arrival on the international stage is one of the reasons why 2025 could be no less eventful than 2024.

Top picture credit: Getty Images

BBC InDepth is the new home on the website and app for the best analysis and expertise from our top journalists. Under a distinctive new brand, we’ll bring you fresh perspectives that challenge assumptions, and deep reporting on the biggest issues to help you make sense of a complex world. And we’ll be showcasing thought-provoking content from across BBC Sounds and iPlayer too. We’re starting small but thinking big, and we want to know what you think - you can send us your feedback by clicking on the button below.