Gordale Scar is a 16million-year-old limestone gorge near Malham that is believed to have been formed after the Ice Age ended and glaciers began to melt, collapsing into the giant chasm.
It has two waterfalls and cliffs over 100 metres high - although thousands of years ago they would have been higher than Niagara Falls.
The stream, Gordale Beck, flows into the famous Janet's Foss pools - a popular picnic spot - before joining Malham Beck.
The ravine is at the northern end of the Craven Fault, a 22-mile geological fault line which runs from Cumbria into the Dales.
Many people believe Gordale could have inspired J R R Tolkien to create Helm's Deep, the valley with a walled fortress that appears in his second Lord of the Rings novel, The Two Towers. In the book, there is a stream running through the gorge.
It's also been suggested that Cheddar Gorge in Somerset, which Tolkien visited on his honeymoon in 1916, could have been the basis for Helm's Deep, but he also spent five years as a professor of English at the University of Leeds in the 1920s, and is likely to have ventured into the Dales during his time there.
What is known for certain is that the famous Victorian artist J M W Turner painted Gordale, and poet William Wordsworth wrote about its beauty.
During the Beast from the East freak weather event in the winter of 2018, one of the waterfalls at the Scar froze and became a 20ft curtain of ice.