It plays host to the most powerful leaders in the world and today 25 lucky winners will walk in the footsteps of presidents in a rare garden tour of Winfield House.
The official American Ambassador's residence in Regent's Park is taking part in Open Square Gardens for the first time this weekend.
The winners were selected at random as part of the secret garden lottery for a chance to look behind the scenes at the grand and historic grounds.
The 5 hectare site is the second largest private garden in Central London after Buckingham Palace.
The venue is steeped in history as the hunting ground of King Henry VIII and the place where Queen Elizabeth I entertained foreign dignitaries.
More recently, distinguished visitors include several American presidents and it's been the venue for high level diplomatic meetings.
Former US President George Bush met the leader of the Soviet Union Mikhail Gorbachev there during the G7 Summit of 1991.
Talks over the Northern Ireland troubles leading to the Good Friday Agreement were also held there.