Tiny (3.5 km2), arid, uninhabited for a long time, it is located in front of the Rhine island (14 km2, uninhabited) and near Mykonos. Tinos, Naxos and Paros are also nearby.

The port has always been exposed to the winds which, as soon as they rise, render the island inaccessible. The site is a UNESCO World Heritage Site. A museum gathers part of the remains discovered on the island.