Officials remove the British flag at the European Union Council in Brussels, Belgium.
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A countdown to Brexit illuminates the exterior of No. 10 Downing Street in London.
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Staff members take down the United Kingdom's flag from outside the European Parliament building in Brussels.
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Jonathan Bullock, a Brexit Party member of the European Parliament, holds a flag as he leaves Brussels to return to Britain.
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British Prime Minister Boris Johnson chairs a cabinet meeting at the University of Sunderland in northeast England.
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Officials arrive for a meeting near the European Parliament in Brussels. At left is European Commission President Ursula von der Leyen. European Council President Charles Michel is at right, and European Parliament President David Sassoli is next to von der Leyen.
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Anti-Brexit protesters hold up a banner on London's Westminster Bridge.
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A commemorative 50-pence coin is pictured at the Royal Mint in Llantrisant, Wales. The coins will enter into circulation throughout 2020 to mark the UK's exit from the EU.
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Anti-Brexit protesters gather outside Parliament buildings in Belfast, Northern Ireland.
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An anti-Brexit demonstrator spreads her wings during a gathering near Downing Street in London.
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Brexiteers celebrate in London.
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Pro-EU activists protest at Parliament Square in London.
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Brexit supporters have their picture taken in Parliament Square.
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