Machaerus

the Black Fortress, was built by Herod the Great in the gorge of
Callirhoe, one of the wadies 9 miles east of the Dead Sea, as a
frontier rampart against Arab marauders. John the Baptist was
probably cast into the prison connected with this castle by
Herod Antipas, whom he had reproved for his adulterous marriage
with Herodias. Here Herod "made a supper" on his birthday. He
was at this time marching against Aretas, king of Perea, to
whose daughter he had been married. During the revelry of the
banquet held in the border fortress, to please Salome, who
danced before him, he sent an executioner, who beheaded John,
and "brought his head in a charger, and gave it to the damsel"
(Mark 6:14-29). This castle stood "starkly bold and clear" 3,860
feet above the Dead Sea, and 2,546 above the Mediterranean. Its
ruins, now called M'khaur, are still visible on the northern end
of Jebel Attarus.