No man deserves a bigger cut of the credit of developing the first wingsuit more than German aviation pioneer, Otto Lilienthal.

Born in Prussia in 1848, Otto Lilienthal was known in his time as “The Glider King.” He was a hero to the Wright Brothers and, today, some consider him the father of flight.

Lilienthal was part engineer, part mad scientist. When he wasn’t writing books on flight dynamics, he was slicing up storks to determine what kept the birds aloft. Eventually, he designed gliders in their image which were remarkably similar to the hang gliders of today. Unlike most modern-day aeronautic engineers, however, Lilienthal didn’t just engineer the flying contraptions, he flew them. He tested out his own inventions, crafted of wire, wax and cloth, and threw himself off higher and higher launch pads.

It all started with a rooftop, just 13-feet high. By 1894, Lilienthal had built an artificial hill near his home to test his 18 gliders. The hill, which stood at a remarkable-for-the-time 49-feet tall, wouldn’t register as a blip on a modern-day BASE jumper’s radar, but was enough elevation for Lilienthal to glide more than 1,000 feet. Unfortunately, it was also high enough to kill him.

On August 9, 1896, a day like any other one of the Glider King’s more than 2,000 flights, Lilienthal’s glider hit an eddy 50-feet above the ground and stalled. Lilienthal swung his body in an effort to point the glider’s nose to the sky, which would have kept the craft aloft, but to no avail. He came crashing down to earth, fracturing his spine, and died the next day in a Berlin hospital.

Today, you can visit his testing grounds at “Fliegerberg,” outside Berlin. The hill remains, along with a monument to Lilienthal. To see his influence in action, check out a modern-day wingsuit pilot. They are the aviation pioneers of today, pushing the boundaries of what we believe to be possible in the skies.

The skies aren’t always friendly, but without pioneers like Otto Lilienthal, we wouldn’t know them at all.