I'd never seen an alligator, and in the space of 2 hours, I got to see about 8 of them, hold one, and have one nearly come up onto the boat! The swamp guides are really informative as well. If you only do one optional, do this one!!

Rayne29 Article on Airboat Swamp Tour

In the summer check out some of the great bars that open along the banks of the River Spree. They often out down sand and call themselves 'Strand Bar' - beach bars!

Mike Contiki Article on Berlin

Itter was one of the nicest town's I've ever been in, absolutely gorgeous. It's a sleepy town, but on Contiki you bring your own nightlife. This was one stop I wont forget.

cdm115 Article on Itter