Hands down it has got to be the name for the Thai capital, Bangkok (heck I don't even know if I spelled it right).

Krung­thep­maha­nakorn­amorn­ratana­kosin­mahintar­ayut
thay­amaha­dilok­phop­noppa­ratrajathani­burirom­udom
­rajaniwes­mahasat­harn­amorn­phimarn­avatarn­sathit
­sakkattiya­visanukamprasit

I love my Thai friends, but I'm glad I don't have a friend with a last name this long :P