The Temple of Poseidon was built in Doric style about 520 b.C. The stones were porous limestone from Aegina. The temple was destroyed in a big earthquake around 395 A.D. The systematic excavations started 1894 by the swedish archaeologists S. Wide and L. Kjellberg. It is very difficult to get a complete picture of what the temple looked like, and that is because of the total destruction of the place. From 1760 the wealthy people of Hydra used this place as a quarry when building their houses.
Demostenes, the famous greek orator, drank poison and died here. He was to be thrown in prison, but refused to submit.