Musée de l'Orangerie

The Musée de l'Orangerie is a gallery of Impressionist and post-Impressionist paintings. The huge (and hugely impressive) Monet paintings - Water Lilies - are definitely the main event, but they are far from the only reason to visit; the museum also contains works by Cézanne, Matisse, Picasso, Renoir, and Rousseau, among others. A superb collection of canvases, in a beautiful and airy setting.
When WWI was coming to close, Claude Monet, one of the founders of Impressionism (the term 'impressionism' comes from a painting he made), offered some canvases to the French state.
He wrote a letter to the Prime Minister stating that, "It's not much, but it's the only way I have of taking part in the victory." His only condition was that his paintings be housed in a suitable venue. The then-underused Orangerie in the Tulieries Garden was just the spot.
The two oval rooms that display the eight massive (2x6m) canvases were partially designed by Monet himself; unsurprisingly they make great use of natural light. These paintings, which showcase his groundbreaking brush techniques, are the undeniable centerpiece of the museum, (and the setting for a key scene in Woody Allen's 2011 film Midnight in Paris ).
It's remarkable that every square inch of each canvas seems to have been treated with the same loving attention to detail and painstaking effort - despite the artist suffering from cataracts at the time.
In addition to the Monets, the museum has a broad collection of Impressionist and post-Impressionist paintings. In another museum, these works - by artists including Matisse, Picasso Cézanne, and Renoir - would be the pride of the collection.
Renovated between 2000-2006, the museum is bright and well-planned (and because it doesn't have the name recognition of the nearby Musée d'Orsay, blessedly less crowded). So, like the characters in Midnight in Paris , take some time to soak up some of the finest art of the 20th century (and seize the chance to see the Water Lilies in a custom-built space).