This man could have started the Industrial Revolution in 50 AD with the invention of the Aeolipile, a form of steam or jet engine where jets of steam spin a ball. However, he failed to realize what the device could do, and thought of it as nothing but a toy. Some have speculated that the abundance of slave labor negated any need for a labor-saving device, so no one applied his device in the manner of the Industrial Revolution. Hero also wrote many works on subjects ranging from pneumatics to mathematics to physics.
Before Wilbur and Orville discovered what would later become the safest mode of transport, they were bicycle mechanics with a passion for kite-flying. The crucial insights from both fields would later propel them to victory in the race to the sky.
Most prototypes of the time could not stay in the air long enough after taking off. The Wright brothers however understood that stability was crucial in overcoming this challenge. After several experiments using kites and gliders, they created a pulley system that altered the shape of the wing in mid-flight, increasing and decreasing the speeds. The Wright brothers were also the first to look at propeller design and aerodynamics, profoundly changing the world.
Henry Ford realized that he would a more efficient way to mass produce cars in order to lower the price. He looked at other industries and found four principles that would further their goal: interchangeable parts, continuous flow, division of labor, and reducing wasted effort. Ford put these principles into play gradually over five years, fine-tuning and testing as he went along. In 1913, they came together in the first moving assembly line ever used for large-scale manufacturing. Ford produced cars at a record-breaking rate forever changing the automobile industry.
Edison is the most prolific inventor in history, holding a record 1,097 patents. He developed the phonograph, incandescent light bulb, stock ticker, motion picture camera and projector, and hundreds more. He also created the first electrical plant and distribution infrastructure. Without these inventions, modern life is almost inconceivable.
Perhaps the biggest visionary of all time, Leonardo foresaw everything from the helicopter to the tank to the submarine. Modern engineers have proven that many of his designs, including bridges, hang-gliders, transmissions, parachutes, and more would have worked had they been built. There have been few individuals in the history of engineering who have designed so many revolutionary devices that actually worked. For having this remarkable vision and intelligence, Leonardo qualifies as the most remarkable engineer of all time.