My family sent me a postcard from the Dalí Theatre-Museum. I have visited it at least twice, and I guess I will find a lot of wonderful details the next time. Salvador Dalí's works are really amazing.
Even the postcard is surprising (sorry the picture is too dark). You can see the museum. Then, you pull the rim...
... and another picture appears. Sort of magic! The title of this painting of 1952 is Galatea of the Spheres.
You can visit Postcards for the Weekend to see more postcards of Museums and Universities.