This is the castle in Odawara, on the way from Tokyo to Hakone.
There are several floors of exhibitions inside the castle. We saw really old samurai uniforms, old swords from 1600 or so, a wooden toy exhibit, miniature models of the castle and plenty more.
Since it is Golden Week (several national holidays in the same week, but you don't really get the whole week off...), there was a huge parade and lots of people dressed up in re-enactment clothes.
Here is the beginning of a parade at the gate to the Castle. They are announcing each prefecture.