Nan Madol is a ruined city in a lagoon adjacent to the coast of Pohnpei in the Federated States of Micronesia, consisting of artificial islands linked by canals. The core of the city contains approximately 100 of these islets and is surrounded by a stone wall.
The name Nan Madol means "spaces between" and refers to the canals, however at one point the name was Soun Nan-leng which meant "Reef Heaven".
It is believed the area began to be settled around 100AD, but carbon dating indicates the megalithic construction didn't start until 1180AD.
The city was the ceremonial and political center of the Saudeleur Dynasty which ruled Pohnpei until 1628 when they were overthrown by external invaders. It was primarily a residence for nobility and religious figures with some islands having special designated purposes such as canoe construction, food preparation, tombs, and coconut oil preparation.
There are no food or water sources within the city and during the Saudeleur Dynasty it was all brought in via boat. Following their overthrow the remaining inhabitants struggled to maintain these supplies and it's thought that this contributed to the eventual abandonment of the city