Nidderdale’s How Stean Gorge, formed in the last Ice Age, features steep chasms and rivers with fossils frozen in its limestone.
It is designated a triple Site of Special Scientific Interest.
Stan Beer, a retired paramedic, bought the gorge in 2007 with wife and former nurse Anne, having been a volunteer at the Gorge since the 1970s.
The gorge’s adventure facilities, with scrambling, caving, canoeing and a high wire, as well as cafe and campsite, have become a popular visitor attraction in the region.
It has recently expanded and increased its main camp site from ten to 20 pitches and is expecting a ‘record year’ for visitors.
Mr Beer said: “We’re set to have our best year yet. The phone has been ringing off the hook, and bookings have increased two-fold.
“We’ve pro-actively moved facilities, built new ones, and employed new staff to meet the public’s demand for outdoor adventure.”
One of the attraction’s additions last year was a glass-panelled bistro over an 80ft gorge, which can seat 70 diners.