Sounion Temple of Poseidon (Neptune), Greece

Cape Sounion (Sounio, Sunium) in Greece is a promontory which was used to spot approaching ships before they reached Athens. Located 65 km south-east of Athens, it is also the site of two famous temples: the Temple of Poseidon and the Temple of Athena. Constructed in the 5th century BCE, the Temple of Poseidon is the best preserved of the two.

Sitting 60m above the sea, many of its 6m high columns remain standing. The temple sites have been popular tourist attractions for centuries. Before the Greek government stepped in to stop the practice, many carved their names into the stone ruins -- including Lord Byron.