A Megalithic Capital
Nan Madol was the political and religious center for the Saudeleur dynasty, which ruled the island of Pohnpei from about 1200 CE. The city is a complex of nearly 100 artificial islets built on a coral reef flat, covering over 18 square kilometers and linked by a network of tidal canals. The name Nan Madol means "within the intervals" referring to these waterways that were the city's thoroughfares. At its peak, the city may have housed up to 1,000 people, including the ruling chiefs and a large contingent of priests.
The islets were constructed by placing large stones and coral fill onto the submerged reef to create raised platforms. Upon these foundations, walls and buildings were erected using naturally formed, multi-sided columns of basalt. Builders used no mortar or concrete; instead, they stacked the basalt logs in a crisscross pattern, a technique known as "header-and-stretcher," relying on the immense weight of the stones for stability. The total weight of the basalt used is estimated to be as high as 750,000 metric tons. Different islets had specialized functions, including canoe construction, coconut oil preparation, and ceremonial activities. The largest structure, Nandauwas, was the royal mortuary, with walls reaching up to 25 feet (8 meters) in height.
An Engineering Enigma
The construction of Nan Madol is an archaeological puzzle. The columnar basalt used for the walls was quarried from a volcanic plug on the opposite side of Pohnpei, more than 25 miles away. Transporting these massive stone logs, some weighing as much as 50 tons, across rugged terrain and open water was a feat of engineering for a society without metal tools, pulleys, or wheels.
Pohnpeian oral history explains the construction through magic, attributing the movement of the stones to the twin sorcerers Olisihpa and Olosohpa, who were said to have levitated the logs into place. Archaeological theories are more terrestrial, suggesting the builders may have used a system of rafts, rollers, and levers to transport the stones. The precise methods, however, remain unknown. The Saudeleur required their subjects and potential rivals to live within the city, a strategy that allowed the rulers to monitor and control the island's elite. The dynasty's rule ended around 1628, when the warrior Isokelekel from the nearby island of Kosrae invaded and overthrew the last Saudeleur ruler. After the conquest, Nan Madol was gradually abandoned and fell into ruin.