Frank Lloyd Wright's Home and Studio in Oak Park, Chicago.
Did the in-depth tour. You can see he used this home and studio to try out ideas that you see in his houses. The Ginko Tree outside the vistors centre.
I wish they would let you take photos inside. Some houses let you and others dont.
One of my favourite things has the huge childrens play room. There was a piano that looks built in, then you discover when you go down the stairs that it is a grand piano with the back of the piano canterleavered over the stair well!!
The Robie House, built in the around 1906. Looks similar to the Martin house in Buffalo that was built around the same time.
If the weather was better, I probably would have checked out more FLW houses.