The Pyramid of Lygourio is one of the most important pyramids in Greece, located northwest of the town, at the foot of Mount Arachnaion. It was built in the 4th century BC and its dimensions were 14 meters long and 12 meters wide.

According to the ancient traveler and geographer Pausanias, the pyramid was built in honor of the fallen in the battle between the twin brothers, Pritos and Akrisios, a battle that ended in a draw. According to Pausanias, the embossed shields depicted in the pyramid are the first reference of the use of shields in battlefields in Ancient Greece.

Researchers argue that the pyramid was built and functioned as a military fort, because along the ancient Argos-Epidaurus road there used to be such forts and this road passed through the foothills of Arachnaion maintain, where the pyramid stands. Others, however, consider it as a burial monument.