16th century, altitude 640m., relative height 80m.
A dirt road starts from the village of Alagni, leading to the top of the hill where the Tholoi (vaults) are located. At the top of a hill with a panoramic view to the west of Alagni, there is a small fortress from the last period of Venetian rule, built during the 16th century or perhaps in the first half of the 17th century. It is a complex of three vaulted ground floor apartments, with a fortified courtyard. This is where the name of the fortress comes from (the vaulted chambers). The initial building had two storeys.
At the foot of Tholon Hill stands the two-aisled church of Agioi Apostoloi (St. Apostles), built in the 15th-16th century, bearing the coat of arms of the Cornaro family. In the church there are two arcosoliums, one inside and one outside, which bear the date ΑΧΙΔ (1614).