Saint Isidore or Cavo Sidero (see also Cavo Sidero Beach) is located at the northeasternmost tip of Crete, 34km east of Sitia, 16 km from Palekastro, and 99km east of Agios Nikolaos.  

The lighthouse was constructed by the French in 1880. The northeastern extremity of Crete is defined by a thin peninsula tipped by Cape Sideros and enclosing the Gulf of Kissamos. The area is also known as Agios Isidoros, "the gift", for a church established there many years ago after a castaway monk came ashore. He built the little church to give thanks to God , since he had been adrift at sea for many days. To have survived the ordeal was, indeed, a gift.

Below the cape is a foundation and parts of columns from a ruined temple to Athena. It was destroyed by an ancient tsumami that swept the coast of Crete after an eruption on Santorini. There is a spring nearby where lightkeepers washed their clothes, and offshore are the sunken remains of several shipwrecks that look like whales swimming on the surface of the sea.

Small islands and large rocks are scattered off Cape Sideros as well as the dangerous Sideros Reef about 600 yards (548 meters) east of the cape. Ships make landfall here and round the cape as they steer in and out of the Libyan Sea. It is a barren area with few inhabitans an ideal place for a monastic existence. However , land developers have taken an interest in the area, and its tranquility is under threat.