Desc: Mysteries of the Sea: Directed by Robert Elfstrom, Al Giddings. With William Holden. 12 underwater photographic essays on marine life - from the stunning opening footage of sharks off South Australia, to the Arctic Ocean beneath the ice cap, to oyster farms off Tahiti. Ending the program, marine botanist Sylvia Earle plants an American flag on the ocean floor, 1260 feet below sea level - then the deepest solo dive in history.