The Mapparium is a fantastic globe which you can climb inside of. The great thing is that from the center everything is in the perfect scale, there is no distortion like there is when viewing a regular globe which projects a convex sphere onto your retina. In this case a degree on your retina, is a degree for the earth, no matter where you look!
Its also interesting as a work of art and history. The map it was based on was from 1934 and they haven't changed it since its opening.
Here is a crazy wide angle photo which super-distorts it but somehow manages to fit the whole room in the picture.