The cave on the hill of Ai Giannis Spiliotis (St. John of the Cave), which is one of the largest in the Aegean, is worth visiting.* The cave is located 171m above sea level and covers an area of approximately 5.600m2. It is engulfed, with a maximum depth of 50m, a maximum length of 89m and a maximum width of approximately 70m. Its arched entrance is 20m wide and the roof is 8m high. The chapel of Ai Ioannis Spiliotis is located at its right side. The vestibule is 22m long, 25m wide and 8m high. It has three levels and the “secret hall” is separated from the vestibule by an enormous stalagmite that has other stalagmites resembling statues on both sides. The walls of the cave, adorned with stone complexes, are awe-inspiring. The most important formation is the so-called “agia trapeza” (altar), with a periphery of 18m and a height of 6m. The hall of “stone waterfalls” and the umbrella-shaped stalagmite are quite interesting. Numerous inscriptions are carved on its walls dating from the antiquity to the recent past. Archilochos, the name of whom is carved on the walls, is considered to be the earliest visitor of the cave of Antiparos. In 1673, the French ambassador Marquis de Nouadel entered the cave using ropes and performed a mass on Christmas Eve over the stalagmite looking like an altar. He was accompanied by painters, builders, designers and monks who stayed in the cave for three days and immortalized their presence there by carving inscriptions on the rock in Latin. The inscription of king Otto who visited the site in 1840 is impressive. * Source: Atlas of the geological monuments of the Aegean/Publication of the Ministry of the Aegean, 2002, www.ypai.gr Info -The temperature of the cave during winter is 15 degrees Celsius and the humidity is 65%. – It is 9km away from Kastro.