When the Berlin Wall came down I leapt on a plane to get my bit of wall. I had to check my hammer and chisel in -- despite publicity saying you wouldn't have to -- and the airline (for the life of me, I can't remember which one, it was a charter run by the German Tourist Board) promptly lost them. Okay, the handling agent lost them, but you know!
Had to ask the friendly locals for bits of Wall and they were most obliging!
Miles off topic, but I got to sit in the jump seat on the way back on what the pilot said were the clearest night conditions he could remember in over 10 years.