Our planet is home to many talented engineers. Termites, for example, build complex structures that rise up to 10 feet in height, their “bricks” bonded by bio-cementation. Spiders, meanwhile, weave intricate webs, which, like suspension bridges, are capable of bearing heavy loads in even the stormiest weather. Then there are beavers and their well-engineered dams, bees and their cellular hives, and industrious ants whose largest recorded contiguous colony stretches a truly incredible 3,700 miles.
Humans, of course, are in a league of their own when it comes to construction. For millennia, we have been building structures of awesome size and complexity: roads and bridges, cathedrals and stadiums, tunnels and skyscrapers. Among the innumerable structures built by humankind, some stand out for their sheer size and magnificence. Here are six of the greatest engineering marvels in history.
The Great Wall of China
The Great Wall of China is widely considered one of the greatest engineering feats of all time. Built continuously from the third century BCE to the 17th century CE, this series of walls and natural barriers stretches for around 13,000 miles. (Still, despite a persistent myth, it is not visible from the moon or space, at least not with the naked eye.) The Great Wall was originally the idea of Emperor Qin Shi Huang, the founder of the Qin dynasty and the first emperor of a unified China, who wished to protect the country from barbarian attacks from the north.
Under his orders, many older, unconnected state walls and fortifications were removed and a number of existing walls were joined into a single system stretching from the eastern Hebei province to Gansu province in the west. The wall itself was 15 to 30 feet high, topped with ramparts of at least 12 feet, with guard towers distributed at regular intervals. Much of the Great Wall that we now see was constructed during the powerful Ming dynasty, starting from around 1474. Today, the most famous and iconic section of the Great Wall of China is located 43 miles northwest of Beijing. This section was rebuilt in the late 1950s and now attracts thousands of tourists every day.