The United States and Cuba are set to abolish one of the last vestiges of the Cold War, by restoring diplomatic ties that have been 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.
From the crack of dawn on Monday (local time), the standard with a white star will also be hoisted up to 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 around 1:45 pm.
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 normalisation 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 on Friday.