State Opening of Parliament
Probably the most colourful event in the UK's legislative calendar, this takes place in May or June every year, or after a general election, when the King travels to the Houses of Parliament to open the new parliamentary session. During this event, the Lords, Speaker of the House

Probably the most colourful event in the UK's legislative calendar, this takes place in May or June every year, or after a general election, when the King travels to the Houses of Parliament to open the new parliamentary session. During this event, the Lords, Speaker of the House
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