Radioactivity is in the water for you and me!
Agios Kirykos supposedly features three hot springs: Mustafa – Litza (Asclepius), Lower Loumakia and Kleftolimano. While I don’t know the exact location of the latter two, Mustafa – Litza seems to be the source of radioactive hot mineral water that used to be pumped to the spa “Asclepius” near the police station. Said spa –big surprise– is not in operation, but the spring is accessible. Just enter the Marina of Ag. Kirykos, go past the administrative building and you will find a concrete pool just under the cliff next to a shipping container.
As with any spring in Ikaria: 20min should be the maximum time you spend due to radon 222 content of the water. Literature says the spring is 43,0°C and 350ME. This probably makes it the most radioactive one that is freely accessible. Beware, everybody said it will really make you dizzy (or worse) if you stay too long!
Mustafa-Litza, Ikaria, Greece: The best spring on Ikaria for sheer perfect temperature and depth. The environment is not as enchanted as the other options. I recommend jumping into the sea at the Marina to refresh yourself afterwards. – bert