Nan Madol
Nan Madol is an ancient city built atop a coral reef in Micronesia. It is believed to be the only ancient city ever built upon a coral reef, but that is just the beginning of what makes this site fascinating. To date, no one has figured out how the people who lived here were able to build it, what tools they used to do it, where they got the stone, or even how they were able to lift up the columns used to make the wall.
Construction on the city is believed to have started by the 8th or 9th century with the megalithic architecture starting in 1200 CE. The city was the ceremonial and political seat of the Saudeleur Dynasty which brought together the 25,000 people of Pohnpei. Pohnpeian legend tells us that Nan Madol was built by twin sorcerers Olisihpa and Olosopha, who used a flying dragon to lift the massive stones.
A single cornerstone of Nandowas, the royal mortuary, is estimated to weigh 50 tons. All the stones moved to the site are estimated to be 750,000 metric tons. An impressive feat for people who had no pulleys, no levers and no metal. Construction of the site took four centuries as it was built in stages but even over 400 years, 1,850 tons of rock would need to be moved and placed each year. Considering the population was only 25,000 that is a monumental undertaking that has yet to be explained.
The city itself was only meant to house 500 to 1000 people. It was a place of residence for the nobility and ruling chiefs. It was also where commoners who could not be trusted were forced to live so that they could always be watched. There was no access to fresh water or food for the people of Nan Madol, it all had to be brought to the city by boat. The city became abandoned in the 17th century but was still used for religious ceremonies up until the late 19th century.