But in the streets of Kyiv, it was relatively quiet.
Ukraine had banned large gatherings and events over fears that Russia could target such civilian gatherings. It followed a warning from the US for any of its citizens to leave ahead of the anniversary.
Some gathered anyway on Khreshchatyk Street to look at the array of captured Russian tanks and armoured vehicles put on display instead of the usual Ukrainian parade.
Between his political speeches, President Zelensky and his wife also attended a memorial ceremony for the fallen soldiers and civilians of the war, laying yellow and blue flowers at Kyiv's Memory Wall of Fallen Defenders.
Earlier this week, Ukrainian officials gave their first update on military causalities in some time - saying that nearly 9,000 soldiers had been killed in the six-month conflict, though that number cannot be independently verified.
Despite the losses, the Ukrainian leader had started the day with a defiant national address, vowing to retake the whole of Ukraine, "without any concessions or compromises".
"We don't know these words - they were destroyed by missiles on 24 February," he said, BBC reported.
"The enemy thought we would greet them with flowers and champagne, but received wreaths and Molotov cocktails instead.
In Russia, meanwhile, the day marking half a year since the start of the invasion passed quietly.
The BBC's Will Vernon in Moscow says there has been almost no mention of the six months of Russia's "special military operation" on television or from officials - possibly a sign that authorities do not want to emphasise the drawn-out campaign.
Russia had initially promised a short, decisive campaign - but Ukrainian resistance quickly pushed Russian forces away from the capital, and months later Russia redeployed its forces to concentrate on the eastern breakaway provinces where it already enjoyed support. In recent weeks, the front lines have hardly moved, according to BBC.
