The unfairly underrated Mycenaean acropolis, 4km north of Nafplio, is the apogee of Mycenaean architectural achievement. Legend has it that its massive walls, 7m thick in parts, were built by a Cyclops. You can stroll around the immense stonework and explore the Upper and Lower Citadels. Look out for the vaulted passageways, secret stairway and impressive gallery, though ongoing restoration means that parts of the ruins may be off limits.
Any Nafplio–Argos bus can drop you here. A return taxi from Nafplio with waiting time is €30.
The site was occupied from the third millennium onwards and the fortifications built in the 14th and 13th centuries BC. This World Heritage site was, in its heyday, second only to Mycenae in terms of regional importance. The layout of some of the ruins is easy to make out, and there are few crowds, though the site has little in the way of signs or descriptions.
In the centre of the upper citadel, you can clearly see the megaron (principal room of the palace) with its column bases. The walls down the middle of it are from a new megaron built after the destruction of the Mycenaean palace.