FREE MUSEUMS (donation recommended) in LONDON are awesome.

Founded in 1824, it houses a collection of over 2,300 paintings dating from the mid-13th century to 1900. …

Its collection belongs to the government on behalf of the British public, and entry to the main collection is free of charge. It is among the most visited art museums in the world, after the Louvre, the British Museum, and the Metropolitan Museum of Art. … 

Overwhelmed, I jumped quite quickly to the the Impressionists and Post-impressionists. My favourites.

In fact, one special exhibition convinced me to buy a ticket.

Courtauld Impressionists: From Manet to Cézanne

The image they used for the promotion is La Loge (The Theatre Box) by by Pierre-Auguste Renoir. (1874)