Da Vinci's Parachute

Perhaps the most distinct aspect of da Vinci’s parachute design was that the canopy was triangular rather than rounded, leading many to question whether it would actually have enough air resistance to float. And since da Vinci’s parachute was to be made with linen covering a wood frame, the hefty weight of the device also was viewed as an issue. Like many of da Vinci’s ideas, the invention was never actually built or tested by Leonardo himself.

Leonardo da Vinci was proved right in June 2000, some 500 years after he sketched the design for the world's first known parachute. A British man, Adrian Nicholas, dropped a prototype from a hot air balloon 3,000 meters above the ground, after ignoring expert advice that the canvas and wood contraption would not fly.