Stone buildings from the ancient city of Nan Madol showed that it's the first to be ruled by a single chieftain.

It located at Pohnpei Island, off the coast of Micronesia. It was said to be once a great city made of stone.

Nan Madol is part of the Caroline Archipelago, a group of islands that can be find in Oceania. It is Micronesia's largest archeological site.

According to Atlas Obscura, the stone building shows the remains of the megalithic architecture of Macronesia.

Mark McCoy from Southern Methodist University explained that this discovery showed the evolution of society. It showed how societies evolved from simple to complex factions.

He explained that the society that we have today came from pre-modern societies like Nan Madol, that was ruled by kings and chieftains. McCoy stressed that by looking at these society you can get insight in society evolution.

He explained that this is a special case because the place developed in isolation. The great thing is that this is supported by oral history.

Researchers found out a burial vault dating back 1200 that contains the remains of the island's first chieftain. Over the next centuries, other tribes followed construction of monumental buildings, Science Daily report.

They reported that the monuments that the researchers found indicated a new society. They also explained that Nan Madol's engineering is a mystery.

McCoy explained that Nan Madol can be compared to Egypt's pyramids. They explained that the monuments were just created as a burial ground for the dead.

"It's not created to make a fairer society or grow food. This shows that it's not just Egypt that created monuments," McCoy explained.

"This is associated with their society and the chief that ruled their island," he explained

Nan Madol was named a UNESCO World Heritage Site. It was said to be established in A.D. 1300.