Washington: The United States and Cuba abolish one of the last vestiges of the Cold War on Monday when, in a move unimaginable just a few months ago, they restore diplomatic ties frozen for half a century.
For the first time since 1961, the Cuban red, white and blue flag will fly over Havana's newly upgraded embassy in Washington, just a stone's throw from the White House.
And from the crack of dawn tomorrow, it will also take its place in a row of flags from around the world which adorn the State Department's imposing marble entrance.
In yet another historic gesture, US Secretary of State John Kerry will also formally receive his Cuban counterpart Bruno Rodriguez for talks, before holding a joint press conference.
Rodriguez will earlier preside over a ceremony to mark the upgrading of the Cuban interests section to a full embassy.
The remarkable turnaround in relations between the communist authorities in Cuba and the US administration after five decades of hostility has happened at break-neck speed.
In what will mark a foreign policy legacy for US President Barack Obama, he and his Cuban counterpart Raul Castro agreed on December 17 to end their estrangement and put their countries on track towards a full normalization of ties.
After a series of negotiations in Havana and Washington, the restoration of diplomatic ties has come about just seven months later.
But both nations have cautioned that this is only a beginning, warning overcoming decades of enmity is not easy.
There are "issues that we don't see eye-to-eye on," State Department spokesman John Kirby admitted Friday.
The United States "wants to move beyond a Cold War- era approach to one of constructive engagement as a way to support and empower the Cuban people," analyst Ted Piccone from the Brookings Institution told AFP.
"Cuba needs the United States as an economic engine for its troubled economy and hopes to attract new foreign investment and human capital to update its socialist model, but without undergoing political reform."
While their approach may be similar, "profound differences" remain and "building confidence and trust will be critical to the ability to move forward."
One of the biggest areas of contention remains human rights, with Washington pressing for an improvement in freedoms of expression, religion and the press in the Caribbean island nation.
Another tough issue is compensation for American property seized after the 1959 Cuban revolution led by Fidel Castro. Some 5,911 lawsuits have been opened in the United States with an estimated value of USD 7 billion to USD 8 billion.