Not since Calvin Coolidge has a sitting U.S. president set foot on Cuban soil. Obama and Cuban leader Raul Castro have been moving aggressively to normalize relations since 2014, when they announced that their two countries would be restoring the diplomatic ties that had been severed since the heights of the Cold War.
Obama, along with his family, will be in Cuba until Tuesday. Among other events, they will attend an official state dinner, and Obama will deliver a speech to the Cuban people.
Below, see some pictures of Havana as it prepared for Obama's arrival.