The article explores Sheffield’s “Megatron”, a vast Victorian-era underground culvert system carrying the River Sheaf and Porter Brook beneath the city centre. It highlights guided urban-caving tours that allow visitors to see this normally hidden infrastructure, presenting it as both a striking piece of industrial heritage and an important part of Sheffield’s flood management.

The route passes through narrow, dark and wet tunnels beneath Sheffield station before reaching the large brick-arched chamber known as the Megatron. Tours are guided for safety and require suitable clothing and footwear, as conditions can be cramped, uneven and affected by water levels; visitors are also asked to respect wildlife, including bats.