Pro-European demonstrators toppled the statue of Lenin, the founder of the Soviet Union, from its plinth in central Kiev as record numbers flooded the city streets.
The crowds had gathered to protest against the Ukrainian government's decision to pursue closer ties with Moscow at the expense of the West.
In jubilant scenes that demonstrated President Victor Yanukovich had lost control of the heart of the capital, the crowd pulled down the statue and took turns with a sledge hammer to smash its marble hulk to bits.
The statue of the Kremlin's first communist ruler is the symbol of Ukraine's shared history with Russia and sits on the main boulevard leading to Kiev's Independence Square.
Russia is the enemy for the hundreds of thousands who marched yesterday to stop Kiev joining a new, Moscow-led customs union.
As if to underline the dilemma confronting the government, as its hopes of riding out the protests fade away, a number of riot police who had been tasked with guarding the statue stood with their helmets in their hands, simply watching.
Officially, the authorities had spent the day preparing to end the disruptions. The security service said protest leaders faced arrest for participating in a coup attempt.
"Today, December 8, data on individual politicians perpetrating illegal acts aimed at seizing power was entered in the universal register of pre-trial investigations," said the state security service, Ukraine's main successor agency to the KGB.
The large crowds demanded the resignation of the president, who infuriated the western half of the country by pulling out of a deal to align it with Europe.
Rallying amid the driving snow, the protesters vowed to maintain their occupation of central Kiev until the government reversed its move.
Leaders of the protest movement, which aims to turn out a million-strong crowd against Mr Yanukovich, said the country was on the "razor's edge" between dictatorship and European democracy.
Vitali Klitschko, the former world boxing champion who is increasingly seen as a president-in-waiting, called on the crowd to maintain pressure on the government.
His call was echoed by Yulia Tymoshenko, the jailed former prime minister, whose daughter, Yevgenia, read out a statement on her behalf.