By noon the next day, a specialized underground survey crew arrived with gas monitors and high-powered lights to explore the passage safely. Robert waited outside the barrier while two investigators descended into the damp gloom of the tunnel.
When the investigators returned thirty minutes later, their faces were streaked with dark grime. The team leader handed Robert a digital monitor displaying photographs taken past the first bend.
The photos showed a widening stone passage scarred with thousands of hand-carved tool marks. The ceiling directly above the entrance was glistening wet. Rainwater filtering through the hillside above was trickling down the roof of the tunnel, collecting dissolved salt from the rock before running straight into the back of the brickwork and soaking through the mortar.