Somerset House is one of the great set pieces of the Strand: a vast neoclassical courtyard facing the Thames, now filled with galleries, exhibitions, events, and places to linger. The Courtauld Gallery is the main draw, with a strong collection of Impressionist and post-Impressionist art.
The building is worth entering even if you are not chasing a specific show. In summer the courtyard fills with fountains and outdoor events; in winter it becomes one of central London's better ice rinks.