The Tailrace Tunnel running behind Niagara Falls was a work of engineering art when it was laid (brick by brick) in 1906, becoming at the time, the largest tunnel of its type in the world. Part of a hydroelectric station, the Tailrace Tunnel expels water back into Niagara Falls which has been used to generate electricity. For the time, few have entered the tunnels, save a few engineers and construction workers. But urban explorers can never resist a challenge and the Tailrace Tunnels proved to be too much for 3 daring travelers. Late one evening, the three seasoned explorers descended upon the facility, stocked with bags of gear, radio communications, drills, lights and everything else one could think of when descending into the belly of a hydroelectric tunnel. Thankfully, they documented each part of the trip, both in pictures and words, creating an extraordinary tale of risk, adventure and some pretty damn spooky experiences.

See more: Explorers document trip through Tailrace Tunnel under Niagra Falls