1. Pamukkale (Turkey)
In Turkish the name literally means Cotton Castle and it is easy to see why it was given that name. Yet this geological wonder is also the site of the ancient city of Hierapolis and over the centuries the two have seemed to come together, almost merged into one. In fact some of the old tombs in the city's necropolis have become part of landscape. The site itself is a series of travertines and hot springs. The travertines here have a concentric appearance and are almost sheer white giving the area an ethereal appearance. The hot springs precipitate calcium carbonate at their mouths and produce the strange almost organic looking structures.