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.
It can be wet and freezing cold and people have reported seeing icicles in winter several feet long.
The tunnel was cut through chalk to carry a railway line between Hull and Barnsley and took three years to complete. A marvel of Victorian engineering, it is the longest of three similar structures along the route of the old line.
The tunnel carried trains beneath the Wolds between Little Weighton and South Cave. But it closed to rail traffic in 1958 and the lines that ran through it are long gone.
Nearby are two other shorter tunnels, one of which could still be walked through until relatively recently. Sugar Loaf Tunnel, which is is 132 yards (121m) long, has now been fenced off, but photographs taken in 2015 show a structure similar to its much longer neighbour. The third, Weedley Tunnel, is also fenced off.
Home to bats
Today, the abandoned Drewton Tunnel is believed to be home to a large colony of bats. A survey in the late 1980s suggested the space was the best home for hibernating bats in the whole of East Yorkshire, an area which does not have any natural caves.
The bats may particularly enjoy the five deep air vents dotted along the line of the tunnel. The top of the vents can still be seen today in the fields around Drewton. They are easy to spot as they resemble large, stubby circular chimneys.
Long lost railway
The Hull and Barnsley Railway was opened in July 1885. Around 8,000 'navvies' (labourers) were employed to build the line and its tunnels. Astonishing images of these men can be seen here.
Little of the railway remains today but for a stretch running to Hull's eastern docks, including a swing bridge over the River Hull. The old passenger station in Cannon Street is now part of Hull College, but the original gates survive.
Decades on, the tunnels slumber under the hills of the Wolds, the rush of steam and the clatter of wheels on tracks a long-distant echo of a lost age.
