Buckingham Palace
The main residence of His Majesty King Charles III, Her Royal Highness Queen Camilla, and latterly of HM Queen Elizabeth II. In the summer, 19 State Rooms are open to the public. Places are strictly limited, and it might not be possible to just turn up and get a ticket for a spec

The main residence of His Majesty King Charles III, Her Royal Highness Queen Camilla, and latterly of HM Queen Elizabeth II. In the summer, 19 State Rooms are open to the public. Places are strictly limited, and it might not be possible to just turn up and get a ticket for a spec
Check the official site before travelling; hours and prices can change.
More museums

Sir John Soane's Museum
Free, tiny, deranged — Soane's own house preserved exactly as he left it in 1837.

The Wallace Collection
Free national museum in a Manchester Square townhouse — armour, Boucher, the Laughing Cavalier.

The British Museum
Free, vast, civilisationally heavy — go for one room, not all of them.
Source: wikivoyage