Why did Putin's Russia invade Ukraine?
When Russian President Vladimir Putin ordered up to 200,000 soldiers into Ukraine, his aim was to sweep into the capital, Kyiv, in days, overthrow its pro-Western government and return Ukraine to Russia's sphere of influence.
Putin failed but, more than three years on, a fifth of Ukrainian territory is in Russian hands.
US President Donald Trump has been pushing for a peace deal, and is set to meet his Russian counterpart in Alaska on Friday, for what the White House has described as "one-on-one" talks. However, previous optimism over an agreement has not led to any progress.
Why did Putin invade Ukraine?
Launching the biggest European invasion since the end of World War Two, Putin gave a fiery speech on TV declaring his goal was to "demilitarise and denazify" Ukraine.
Russia has repeatedly painted modern Ukraine as a Nazi state, in a crass distortion of history.
Putin had already seized Ukraine's Crimean peninsula eight years earlier, after a revolution that ousted Ukraine's pro-Russian president and replaced him with a more pro-Western government.
Putin then triggered a lower-level war in Ukraine's eastern Donbas region, with pro-Russian proxy forces occupying territory and setting up rebel states supported by Moscow.
But the 2022 invasion was on a different scale.
Putin had just recognised the rebel states as independent. Then, as the invasion began, he said the people there - many of whom are Russian speakers - needed protection from the Kyiv "regime".
A day later, Putin called on Ukraine's military to "take power into your own hands" and target the "gangs of drug addicts and neo-Nazis" running the government.
He then added another objective - to ensure Ukraine stayed neutral. He accused the Western defensive alliance, Nato, of trying to gain a foothold in Ukraine to bring its troops closer to Russia's borders.
The Russian leader has long questioned Ukraine's right to exist, claiming that "modern Ukraine was entirely created by Russia" after the communist revolution in 1917.
In a long-winded 2021 essay he even suggested "Russians and Ukrainians were one people" dating back to the late 9th Century. Last year he told US TV talk show host Tucker Carlson that Ukraine was an "artificial state".
Those comments have led many to believe that the goal of the invasion was in effect to erase the state of Ukraine.
Russia's state-run Ria news agency explained that "denazification is inevitably also de-Ukrainisation" - seemingly tying the idea of erasing Ukraine to the stated goal of the invasion.
Ukrainian culture and identity have in fact existed for centuries independently of Russia.
Fact-checking Putin's 'nonsense' history
Zelensky - from comedian to wartime leader
Does Putin want to get rid of Zelensky?
Putin has long sought to get rid of Ukraine's elected pro-Western president, and Zelensky was apparently a target from the very start of the war.
Russian troops made two attempts to storm the presidential compound soon after the invasion, according to Zelensky's adviser, and Ukraine's elected leader said they wanted him dead.
"The enemy has designated me as target number one; my family is target number two.
"They want to destroy Ukraine politically by destroying the head of state."
Zelensky said later that Putin had initially tried to replace him with the wealthy head of a pro-Russian party, Viktor Medvedchuk, who was accused of treason in Ukraine and is now in Russia.
Even now, Putin has not agreed to peace talks with Zelensky and his officials call him a "loser" and a "clown". He has spoken of the Ukrainian leader's "illegitimacy" - a false narrative that has also been repeated by Trump.
As evidence Putin cites the postponement of Ukraine's March 2024 presidential election, although it is because of Russia's war that Ukraine is under martial law and elections are barred under the constitution.
Putin's own re-election in 2024 is highly questionable, as Russia's opposition leaders are either in exile or dead.