The round tower, one of the best-preserved ancient monuments, is situated on the northern slopes of Megalo Vathychori. It has a diameter of 6.2 meters and is 12.5 meters tall. It is constructed in the trapezoidal-isodomic style. The entrance in the southern part preserves cuttings for the support and barring of the door.

This impressive monument had four storeys, as is evident from the three rungs of joist-holes visible on the inner side of the wall for the beams that supported an equal number of floors. The upper storey had six windows, all of the same size, above which there was evidently a pitched roof so that rain water could be collected through a spout preserved on the east side at the floor level of the 4th storey. The archers? slots, better observed from the interior, and the windows for small catapults place the tower in the military category. However, it must surely have functioned to guard cultivated areas in times of peace. It is bounded by a circuit wall, the masonry of which is better preserved on the south side.

The circular tower is one in a series of at least six towers that controlled the road leading through the Vathychoria to Boeotia. One of these, the square tower of Vathychori (5 x 5 m.; height 10 m.), stands some 500 meters southeast of the round tower on the rural road to Mikro Vathychori. It too preserves archers? slots, windows, a water spout, and an entrance on its south. Traces of an enclosure wall and a small settlement have also been found.

The towers of the Vathychoria, belonging to the 4th century B.C. defense system of the Megarian region, guarded this mountain road in order to ensure safe passage for the armies marching from the Peloponnese to Boeotia. This is the road that was taken by troops when they wanted to avoid the Athenians, who controlled the more even road to the east beyond the mountain road.

On the slopes and peaks that enclose the Vathychoria, traces of residential and rural installations in addition to other towers provide evidence of intense activity in that rough territory, which was especially important for the history of the Megarid during Classical and Hellenistic times.