And no one can figure out how it was built in the first place.

Nan Madol ruins in Pohnpei, Micronesia
Credit: Michael Runkel/Getty Images

Satellite images are shedding new light on a mysterious city built on an island in the middle of the Pacific Ocean.

Explorers first discovered the ruins of Nan Madol nearly 100 years ago, on the island of Pohnpei in Micronesia, the Independent reported. The island is situated about 1,600 miles from Australia, and 2,500 miles from Los Angeles, California.

Some locals in Pohnpei refuse to go near the ruins of the city, believing it to be haunted, according to the Independent. Horror writer H.P. Lovecraft even took inspiration from Nan Madol for the fictional, sunken city of R’lyeh in one of his short stories.

“Why would somebody build a city out in the middle of the ocean?” archaeologist Patrick Hunt said in a new episode of the “What on Earth?” show on the Science Channel, which discusses the satellite images. “Why here, so far away, from any other known civilization?”

The city, which thrived from 1200 to 1700, was built on coral reefs, and is connected via a series of canals. Nan Madol served as a major political and religious city in Polynesia, and some locals call the ruins “Soun Nan-leng,” meaning “Reef of Heaven,” according to the Pohnpei Visitors’ Bureau. The ruins include tombs, baths, and temples.

Nan Madol ruins in Pohnpei, Micronesia
Credit: Getty Images

Nan Madol is made up of 92 artificial islands spread across 200 acres, Smithsonian Magazine reported. Some of the walls are 25-feet high, and the total weight of black rocks totals 750,000 metric tons, making it a larger undertaking than the Egyptian pyramids, according to the same report.

Without the use of pulleys or other tools, the mystery lingers as to how the city was ever built.

“We don’t know how they brought the columns here and we don’t know how they lifted them up to build the walls. Most Pohnpeians are content to believe they used magic to fly them,” an archeologist from Pohnpei told Smithsonian.