The Propylaea is an ancient gateway in Athens, Greece that leads to the famous Acropolis. It surrounds the natural entrance to the plateau where the Acropolis is located. This entryway is actually a collection of impressive buildings that were built from 438 to 432 BC. Today you'll see two large structures with a smaller one in the center, but this is because most of the center structure is missing. When it was complete, it looked like the front of a temple with Doric columns. Inside the structure are several Ionic columns.
The stairway visitors walk up while approaching the Propylaea is built into the natural rock of the plateau. The Propylaea itself is made of the same marble that was used in constructing the Parthenon. Though it is in a ruined state today, it is still an impressive structure, and visitors can imagine how much more striking it must have been in ancient times.
The Propylaea is located at the entrance to the Acropolis. To get there, take the metro to Acropoli. Acropolis opening hours are 8am to 6:30pm daily, and admission is 12 euros.