For those in the Bay Area I highly recommend the Marin Museum of Bicycling. They have an absolutely incredible collection and walking through it you can actually see the bicycle evolve from the direct pedal to today's designs. Truly wild to see some of the dead end evolutionary branches. Steering mechanisms, gearing, early chains, brakes -- people tried so many crazy approaches.

It was founded by a lot of the original mountain bikers so it has a lot of the evolution of mountain bikes as well.