>> the 10th century b.c. is the last time anybody actually really sees it according to the biblical tradition. now, there are other stories. and these all are related to the babylonian destruction of the city in 536 b.c., that maybe somebody spirited the ark out of the city just ahead of the destruction. >> reporter: many believe these underground tunnels were used to secretly transport the ark out of jerusalem when the city was under siege. and when the babylonian invaders took detailed inventory of the treasures they plundered, something was missing. >> the babylonians took all the treasures from jerusalem, it was not in the list anymore. >> the ark? >> yes. the ark was not in the list. >> there are all kinds of possibilities as to where it ended up. >> reporter: so we went in search of it. one famous story suggests the