Symplegades

thumb|Illustration by Howard Davie for The Heroes by [[Charles Kingsley.]] The Symplegades (; , Symplēgádes), also known as Clashing Rocks or Cyanean Rocks (Κυανέαι), were, according to Greek mythology, a pair of rocks at the Bosphorus that clashed together whenever a vessel went through. They were defeated by Jason and the Argonauts, who would have been lost and killed by the rocks except for Phineus's advice. Jason let a dove fly between the rocks to see exactly how fast they would have to row to beat the rocks; the dove lost only its tail feathers. The Argonauts rowed mightily to get through and lost only part of the stern ornament. After that, the Symplegades stopped moving permanently.

thumb|Rocky islet at Rumelifeneri The European rock is usually identified with an islet, about wide and long, which stands about off the shore of a village called Rumelifeneri ('Lighthouse of Rumeli'), and is connected to it by a modern concrete jetty. At its highest point, there is an ancient altar known as the Pillar of Pompey, though it has nothing to do with Pompey. Dionysius of Byzantium mentions a Roman shrine to Apollo on one of the Cyanean Rocks, and the 16th-century French traveller Petrus Gyllius thought the altar was a remnant of that shrine.