The president and first lady then boarded Marine One, the presidential helicopter, which will take them to London. Their first planned event is a meeting with U.S. Embassy workers at the American School in London.
The president will visit five countries on his eight-day European swing: the U.K., France, Germany, the Czech Republic and Turkey.
He will meet with European leaders, attend a NATO summit, and participate in the G20 conference, where he will try to convince skeptical Europeans leaders to follow his lead and inject further stimulus funding into their economies as part of a coordinated response to the global financial crisis.
Read all about the president's plans and schedule here.