Restoration workers discover nine secret crypts hidden under the ruins of Coventry's bombed cathedral.
Work has been taking place after a crack appeared in part of the 14th Century ruins, in September 2011.
It was already known there were two crypts, which were last open to the public in the 1970s.
Dr Jonathan Foyle, the chief executive of the World Monuments Fund, which is overseeing the work, said it was like finding a "subterranean wonderland".
He said it was hoped the crypts could open to the public once they had been damp-proofed and cleared of rubble.
It is thought the crypts were originally used as special burial places for the nobility. Some contain human bones, which are thought to have been cleared from the cemetery which was built on for the new cathedral.