The Wallace Collection is an amazing place, a stately mansion stuffed with paintings, furniture, trinkets, and arms and armor that reads more "collection" than "museum." Mixed with the world-class paintings by Fragonard, Rembrandt, and Rubens, among others, are busts and bronzes, Italian ceramics, French porcelain, and two enormous Chinese incense burners. It's easy to walk around in a daze since the painting are stacked two or three deep on high ceilinged walls, the furniture is all works of art in their own right, and there are consoles with drawers you can pull out to admire, say, a collection of miniatures depicting Napoleon and Josephine. Wander through for a while then go get a drink at the cafe to regroup for another pass through before you go. It's real London treasure and, like all the public museums, is free.