Interesting Sites and Monuments: Castle, Bay of Meriha, and Papas Hill
Kastro (castle) of Livadi: These are the remains of a castle of Hellenistic Period (323 b.c-316 b.c.).
Also found are the ruins of the temple of Zeus and that of the Goddess of Luck. It was a settlement until 1930
The Bay of Meriha: it is surrounded by cliffs more than a hundred meters high. Birds find natural nests inside the openings in the cliffs.
Papas Hill: from where one can admire the view of all the islands that are around Iraklia. From this point bird-watchers can indulge in their hobby because some rare species of birds can be spotted from here.

The Cave of Agios Ioannis

When in Iraklia one can visit the cave of Agios Ioannis (St. John). It’s the biggest cave of the Cyclades and one of the best in Greece. Consists of a maze of incredible stalactites, stalagmites, columns and a rare kind of ''cave-milk'' and it takes two and a half hours to explore it. It is situated at a panoramic site with full view of the sea and nearby island. From the village Panagia it takes one hour to walk to the cave.

Legend has it that sometime at the end of the 19th century, a shepherd had lain down under a bush to seek refuge from heavy rain. When he later reached the village, his friends noticed that at the back of his shirt there was the face of St. John the Prodrome. They asked the shepherd to show them were he had lain, and when they got there they discovered the entrance of the cave and icon (painting) of St. John the Prodrome. That's how the cave got its name, and every year on that day, the celebration held in memory of the beheading of St. John, vespers are held at the big hall of the cave and visitros from nearby island as well as tourists attend.

More info about the cave