The South Bank Lion
This statue was once the mascot of the Red Lion Brewery and stood on its roof until the brewery was demolished to make way for the Royal Festival Hall. It was moved to Waterloo and then to its present position on the bridge. Keen students of biology may notice that the statue is

This statue was once the mascot of the Red Lion Brewery and stood on its roof until the brewery was demolished to make way for the Royal Festival Hall. It was moved to Waterloo and then to its present position on the bridge. Keen students of biology may notice that the statue is
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