I am the bat.

At half past ten on the morning of December 17, 1903, the Wright Flyer I went airborne four miles south of Kitty Hawk, North Carolina, and flew into history. At the controls of the spruce-and-muslin aircraft was Orville Wright; he flew 120 feet in twelve seconds, at an altitude of roughly 10 feet. On some subsequent flights, his brother Wilbur piloted the machine.

The brothers have been (justifiably) lauded for their pioneering work on powered aircraft, but they didn’t invent in a vacuum. Indeed, they found considerable inspiration in the work of Otto Lilienthal, a towering figure in the early history of flight, but whose contributions were somewhat overshadowed in subsequent decades by the Wrights’ accomplishments.

“Lilienthal was without question the greatest of the precursors, and the world owes to him a great debt,” Wilbur Wright would write in September 1912.

Lilienthal was a German engineer and a student of aerodynamics. His early ideas for human-powered flight came from birds; of the various gliders he designed, a few even included flapping wings. Those gliders very much resembled their modern equivalents, with the pilot hanging on a frame beneath the wings; and although Lilienthal struggled mightily to balance the weight of his designs, they had a tendency to pitch forward — which would have fatal consequences.

Once he translated his designs from ink and paper to wood and cloth, Lilienthal would launch his gliders from hills, including a man-made one (dubbed “Aviation Hill” or “Fly Hill”) he constructed near Lichterfelde, outside of Berlin:

Wheee!

By 1890, he had a machine capable of gliding a little over 80 feet; three years later, more than 800 feet. He never created an engine that would reliably enable powered flight, but he did contribute quite a bit of research to wings: their curves, surfaces, aspect ratio, and other elements necessary for a significant amount of weight to slip the surly bonds of earth.

Neither Lilienthal nor the Wright brothers were isolated in their pursuit; as the 19th century came to a close, researchers all over the world were probing at the fundamentals of aerodynamics. Many came to hear Lilienthal lecture; at one such talk, in 1894, he confessed: “I have to admit that it will still take quite a lot of work to turn this simple gliding flight into long distance human flight. The achievements so far for human flight are nothing more than were the first insecure steps of a child related to the walking of men.”

But Lilienthal would never live to see the dream of powered flight realized. During a flight in August 1896, his glider pitched forward, sending him plummeting 50 feet to the ground. His neck broken, he died the next day. His last words, reportedly, were “Opfer müssen gebracht werden,” which translates to: “Sacrifices must be made!”

That wasn’t just a comment on his own fate; it was a prophecy for the next century, as many died trying to perfect human flight. But without those dreamers —some of them calculating, some of them mad —we might never have left the ground.