A huge tunnel that runs under Niagara Falls is now open to the public.
The 2,200-foot tunnel, located six levels beneath a hydro power plant, was built more than a century ago to allow water to pass through, according to Marcelo Gruosso, senior director of engineering and operations with the Niagara Parks Commission.
The tunnel diverted water from the Niagara River to run giant generators. The water would turn turbine blades, which generated electricity for the surrounding area.
"It took thousands of workers four years to excavate the shale beneath the main generating room using lanterns, dynamite, pickaxes and shovels," Gruosso told CNN. "The tunnel held 71,000 gallons of water that moved at nine meters per second."
The tunnel is made up of four layers of brick and 18 inches of concrete, and is surrounded by shale.
"We did some minor brick repairs and added rock anchors to the arch to ensure structural integrity, but it's in really good shape," Gruosso told CNN. "They only ever did maintenance twice since it was built, once in the 1950s and once in the 1990s."
The 117-year-old power plant, which has since been decommissioned, has been offering tours for several years -- and now a walk through the underground tunnel is part of the tour.
"This all-new attraction uncovers a never-before-seen underground world and reveals more fascinating details about Niagara's incredible story of power," the attraction's website states. "Make your way down into the tunnel in a glass-enclosed elevator and prepare to witness a breathtaking panoramic view of the falls from the viewing platform at the edge of the Niagara River."
The tunnel -- 180 feet underground -- served as an exit point for the water used in generating hydropower for over a century. The journey through the tunnel takes visitors along the same path travelled by water and leads to a viewing platform where the tunnel emptied into the Niagara River, offering unprecedented access to a new perspective of the lower Niagara River with unparalleled views of both the Horseshoe and American Falls.
The all-new tunnel experience at the Niagara Parks Power Station is included with regular admission, which costs $28 for adults (13+) and $18.25 for kids (6-12). If you want to add a fully guided tour to your trip, tickets are $38 for adults and $25 for kids.
Officials recommend planning for a two-hour experience if you wish to explore the tunnel during your visit to the power station.