The Herodion, the great first-century-B . C . pleasure palace of Herod the Great, looks like a faraway truncated volcano in the desert distance; and the tremendous, towered, eyeless walls of the 6th century monastery of Mar Saba, where a dozen monks still live, are only a few miles away, clinging to the 300-foot cliffs of a huge, fissured water course leading down to the Dead Sea.