Britain has left the European Union after 47 years of membership, taking a leap into the unknown in a historic blow to the bloc. Brexit became official Friday at 11 p.m. in London and midnight in Brussels, where the EU is headquartered. Thousands of enthusiastic Brexit supporters gathered outside the U.K. Parliament in London cheered as the hour struck. In a recorded message, British Prime Minister Boris Johnson called Britain's departure as a moment of real national renewal and change that would lead to a bolder, more energetic nation. But many Britons mourned the loss of their EU identity. And there was sadness in Brussels, where British flags were quietly removed from the bloc's many buildings. Bidding a sad adieu to the first country to leave the European Union, French President Emmanuel Macron called Brexit a historic alarm signal that should force the EU to improve itself.