The East Side Gallery is the longest surviving section of the wall, and it's covered in some pretty historic murals, originally painted right after it fell in November 1989. It's crazy to see what a pathetically thin slab of concrete separated two different worlds within the same city.
Sadly the murals are decaying. They were freshened up by the original artists in 2000, and so when I first saw them in 2002 they looked pretty good. By 2004 they were a bit rough-looking, and now in 2008 it was really depressing to see how awful they looked. In a city with no shortage of places to spray a bit of graffiti, I couldn't understand why so many people would choose to spray it here.