Herod’s tomb was not easy to find: A Franciscan monk excavated Herodium from 1956-1962. The area was captured during the six day war and given over to Netzer. The failure to find Herod’s resting place was taken to be somewhat of a mystery that is now put to rest.
Herodium was pegged as the site of Herod’s tomb on account of Josephus Flavius’ account of his death. Thanks to Haaretz for a slightly premature but interesting announcement.