HAVANA - President Barack Obama is in Cuba for a historic three-day visit to the island and talks with its communist leader.
He is the first sitting US president to visit since the 1959 revolution, which heralded decades of hostility between the two countries.
Speaking at the reopened US embassy in Havana, he called the visit "historic".
Mr Obama will meet President Raul Castro, but not retired revolutionary leader Fidel Castro, and the pair will discuss trade and political reform.
President Obama's visit is the high point of a recent easing of ties between the US and Cuba, which included the re-establishment of diplomatic missions last year.
Unsurprisingly, his first stop was the newly re-opened embassy.
Mr Obama, who is the first sitting US president to visit Cuba in 88 years, told staff: "It is wonderful to be here."
"Back in 1928, President [Calvin] Coolidge came on a battleship. It took him three days to get here - it only took me three hours. For the first time ever, Air Force One has landed in Cuba and this is our very first stop."
Later on Sunday, he toured Havana's old town with his family, huddling under umbrellas to shelter from a tropical storm before visiting the national cathedral.
Security was tight and the historic city centre looked uncharacteristically empty. One Cuban shouted: "Down with the embargo!"
President Obama responded by waving.
The 54-year-old US trade embargo is one of the main sticking points in US-Cuban relations.
It can only be lifted by the US Congress, which is controlled by Republicans who have expressed their opposition to its removal.