Palaiokastro peninsula (maybe there was a castle there but there is no information that verifies the existence of a building) surrounds the port from the west side. The cobblestone stairs lead to two chapels, of St. John the Baptist and of St. Anna. The three flags (Greek, byzantine and of Psara) are flapping. At the south part of Palaiokastro, Mavri Rachi offers shiver and awe to the visitor. At the north part you will see Kato Gialos beach.
During the Greek Revolution, people of Psara brought to this place cannons, built an emplacement that was used as a fort and dug a hole in the ground that was used as powder warehouse. On the 22^nd of June 1824, after a heroic effort, 120 fearless warriors chose to be blown up instead of ending up in the hands of Turks. Today in memory of the immortal defenders of the island there is a monument on the steep massif and the rest of the remains with this simple inscription: “In memory of the immortal heroes of the Holocaust of Mavri Rachi”.