This museum in Kannai is either free or they let us in for free because of my mothers wheelchair.
In any event, multiple floors of beautiful exhibits and a really nice lady happened to see us and took it upon herself to guide us (in Japanese, I don't know if she speaks English).
She explained that the building itself survived the earthquake in the early 1900s (I don't remember the year) which explains the interesting mix of old and new buildings throughout Yokohama.
Completely worth the trip if one is in Yokohama, only a few blocks from Kannai station.