Museums are fantastic places to take candid and street photos. Often the light is inspiring. There is a lot of space, big walls, colors, lines and curves. This gives you a good framing to place your subject in. Most visitors are concentrating on the art, and others bring their camera too. So the risk of getting noticed as a candid shooter is little.
Try it out yourself. Even if art and museums doesn’t interest you. The possibility of taking interesting pictures is there. Just be sure that photographing is allowed.