The hammer in the ceiling.

Above the tunnel entrance a hammer had been cemented into the ceiling by one on the slave workers. This is indicated by blue rectangle in the picture above.

The Hospital has a floor space of 27,611 square feet in the completed portion.

Approximately 27,937 cubic feet of rock (about 13,600 tons, have been excavated from the completed part of the hospital.

About 4,000 tons of concrete was used to line the galleries and walls.

In the central unfinished corridor the Germans have sunk a large well making the Hospital completely independent of outside sources for its water supply.