Monemvasia is a castle town on a small island just off of the coast of the Peloponnese that played a significant role during medieval times. The island is connected to the mainland by a 200-meter causeway, and the town itself was carved into the side of a sea rock, so as to be invisible from the mainland, providing protection from attackers. It is also the former site of a fortress. Several medieval features are still visible, including the original town walls and a number of Byzantine churches. Many old mansions are still present but have been turned into accommodations for tourists. The top of the castle offers stunning views of the sea, which are a must-see. Map