The Vrykolakas of Santorini

Santorini has long been considered the capital of the vrykolakas — the Greek undead. In the 17th century, Father Richard, a French Jesuit missionary, documented dozens of cases of corpses that refused to decay and were said to roam the island at night, knocking on doors and calling out to the living. Those who answered a vrykolakas call were said to die within nine days.

The volcanic island's unique pumice soil, which naturally mummifies bodies, gave the legend scientific grounding. Even today, locals on the island's northern tip near Oia report hearing three slow knocks on their doors after midnight — never more, never less.