As recent as 2,000 years ago, Tienmanshan was merely a mountain in northwest Hunan, China. It had long been praised by emperors and mystics as a place where the earth and the heavens met.

Then, in the second century, a massive limestone slab calved from the middle of the mountain and a “cave” was born. Today, most people visit Tianmen Cave to climb the 999 steps and walk through what translates to “Heaven’s Gate.”

Wingsuiter Jeb Corliss is not like most people. Last September, he fell from a helicopter and flew through the hole in the mountain. It might be the most incredible wingsuit stunt ever attempted.