House of Lords Strangers' Gallery
If you head away from the Commons, you pass along a corridor towards the Lords. If you ask to visit the Strangers' Gallery, a representative of Black Rod asks you to complete another slip of paper with your name and address. You then proceed up a staircase to the Lords Strangers'

If you head away from the Commons, you pass along a corridor towards the Lords. If you ask to visit the Strangers' Gallery, a representative of Black Rod asks you to complete another slip of paper with your name and address. You then proceed up a staircase to the Lords Strangers'
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