Nan Madol: A City on Artificial Islands

Nan Madol sits off the eastern shore of Pohnpei, built between roughly 700 and 1600 CE by the Saudeleur dynasty that ruled the island. Rather than build their capital on solid ground, the Saudeleur raised nearly a hundred small artificial islets inside a shallow lagoon, separating the islets with a grid of tidal canals. A capital surrounded by water controlled access, displayed the ruler's power over labor and stone, and kept the royal center physically apart from the rest of Pohnpei's population.

The walls are made of prismatic basalt columns, naturally hexagonal rock formed when thick volcanic lava cools slowly and cracks into long crystal-like beams. Workers quarried these columns already shaped this way and stacked them log-cabin style, alternating the direction of each layer the way you'd stack notched logs, to build walls up to 7 meters high at structures like Nandauwas, the mortuary islet at the city's center. Laying columns in alternating header and stretcher courses, some ends facing out, some sides facing out, locks each layer against the one below it and keeps a wall of loose, mortar-free stone from toppling or sliding apart.

In plan, Nan Madol reads as a capital turned inside out: canals function as streets, islets function as building lots, and Nandauwas occupies the most prominent position, closest to the open sea, reserved for the dead rulers it housed. The site sits alongside other Pacific topics built around environment and engineering, from wayfinding canoes read against swell and star to the moai of Rapa Nui, each showing how Pacific societies built monumental culture from what their islands gave them.