A gigantic disused railway tunnel beneath the Yorkshire Wolds hides a space so large, it's believed to have its own climate.
The Drewton Tunnel - which at 1.2 miles is one of the longest abandoned tunnels in the UK - has been closed to all but a few intrepid explorers for the past 60 years due to various dangers such as falling chalk.
The entrances at each end are blocked, with one almost completely buried by landfill from a quarry. But those few who have been inside describe a huge, vaulted space, lined with orange coloured bricks.
