Rethymno mountains have 850 caves of extraordinary natural beauty with archaeological, historical and folklore interest. The most known caves in Rethymno are the Gerani and the Simonelli cave west of the city, Agios Antonios in Patsos Amari, Melidoni cave, Idaion Antron, Mougri cave in Sises, Sfendoni cave in Zoniana etc.

Idaion Antron
In Nida plateau in Psiloritis, 24 km from Anogia and 78 km from Rethymno is situated Idaion Antron. Idaion Antron is located at an altitude of 1,538 m. It is a large cave with a large chamber and a 22 m long gallery. The cave where Zeus was brought up according to myth had been an important place of worship in Minoan and Roman times. The excavations have brought to light rich and important findings among which pottery, gold jewellery, metal objects and bronze shields. Because of research inside the cave, it is closed to the public.

Melidoni Cave
The excavations in Melidoni cave have revealed that the cave was used as a place of worship from the early Neolithic period until the Roman Empire. According to an inscription it is connected with the worship of Hermes. The cave played an important part in recent years, mostly during the Ottoman occupation when 370 residents of Melidoni surrounded by Turks died from suffocation in the cave in January 1834. Their bones are kept in the first chamber of the cave. The cave is open all year round.

Gerani Cave
In Gerani cave there are marvellous stalagmites and 6 chambers; the archaeological research has brought to light apart from three human skeletons, a great number of bone and stone tools of Neolithic age. It has also been found major fossil finds from one hundred indigenous deer that must have died at the end of the Pleistocene Epoch. The skeletons belonged to people who were trapped in the cave probably due to earthquake.

Sfendoni Cave
Sfendoni cave in Zoniana Milopotamos (47 km from Rethymno) has 14 chambers with rich stalactite and stalagmite ornaments. It is 550 m long and it extends in 3,330 sq.m. Over the last years, archaeological research has brought to light Neolithic age remains in the cave. The cave is open to the public.

Agios Antonios Cave
Agios Antonios cave in Patsos is another cave that had been a place of worship from late Minoan to Roman years. According to an inscription in the cave, this was a sanctuary of Hermes Kranaios. The church in the cave is dedicated to Agios Antonios, who protects children. The cave is open to the public.