Semystra
Semystra was a town of ancient Thrace. Dionysius of Byzantium wrote that there was an altar of Semystra there, whence the name of the town. Semystra was a nymph, she nurtured the Keroessa, who was the daughter of Io and Zeus.
Dionysius added that Semystra nearly became a big city during the Greek colonization since the leaders of the colonization made the founding of the city, but during the sacrifices, a crow snatched one of the thighs from the middle of the flames and carried it to the Bosporion promontory. The rest of the Greeks saw this as a sign from Apollo and went to the spot were the crow has left it.
Its site is located at the head of the Golden Horn in European Turkey.