World Heritage: Exploring Micronesia's Nan Madol

Theories abound as to who built Micronesia’s UNESCO-listed floating city – was it sorcerers, aliens, a ruthless dynasty? But the questions only make it more exciting...

4 mins

Several years ago, a TV history channel featured Micronesia’s obscure archaeological wonder, Nan Madol, in a series called Ancient Aliens. The show wheeled out a string of historians – more Indiana Jones than Lucy Worsley – who speculated how uncertainty surrounding the floating city’s origins in the western Pacific Ocean might suggest builders from another planet.

It’s a tempting theory considering Nan Madol’s hard-to-reach location. This large and sophisticated ceremonial complex is constructed on a coral reef wrapping the tiny Temwen Island, which lies off the shores of Pohnpei, itself part of an archipelago in the Federated States of Micronesia that is surrounded by thousands of kilometres of ocean. That’s about as remote as any UNESCO World Heritage-listed site gets.

Even the likeliest creators of this floating city, the Saudeleur Dynasty, are somewhat mysterious. Little is known about them, although island oral history recounts the sudden appearance of twin sorcerers, Olishpa and Oloshpa, magicking blocks of basalt through the air to construct an altar on Temwen. Back in the corporeal world, it is believed that the Saudeleurs arrived on Pohnpei and started building Nan Madol in the late 12th century. Their rule only ended after they were usurped in battle in 1628 by a chief called Isokelekel, causing the ceremonial status of Nan Madol to eventually fade into obscurity.

Kepirohi Waterfall near Nan Madol (Shutterstock)

Kepirohi Waterfall near Nan Madol (Shutterstock)

An Aerial view of Nan Madol (Shutterstock)

An Aerial view of Nan Madol (Shutterstock)

Structurally, the complex spans some 100 artificially created islets made up of platforms of basalt rock built atop the reef. Its lofty walls enclose the Atlantis-like marine ruins of palaces, mortuaries, workers’ residences, altars and temples within 60 hectares. These islets are divided by sea-filled waterways, so would have been navigable by boat. Western observers naturally lent it the sobriquet the ‘Venice of the Pacific’; in Micronesian parlance, Nan Madol rather prosaically translates as ‘within the intervals’, which also defines the city by its intricate web of canals.

UNESCO lists Nan Madol as the earliest example in the Pacific of a huge-scale megalithic structure. Its design reflects the complex religious and social practices that operated within a system of paramount chiefs (known as Nahmwarki). It is speculated that, during the city’s heyday, up to 1,000 people may have inhabited its walls, including local chiefs and priests as well as all of their servants. Historians believe the Saudeleur rulers probably used it as a form of social control, keeping potential enemy chiefs across Pohnpei beneath their wing by housing them within the walls of the city.

It’s the air of mystery surrounding this civilisation that excites the few travellers that make it here. Getting to explore Nan Madol isn’t easy, and whether taking a boat or taxi from the main town of Kolonia, only a limited amount of the ruins are visitable amid the coastal mangroves. If a drone would be the best way to truly appreciate its scale and layout, a local guide is essential to help navigate, not least when wading or taking little canoes across the waterways.


The vast hexagonal columns of basalt used to build Nan Madol are thought to have been mined on Pohnpei and transported to Temwen using raft (Shutterstock)

The vast hexagonal columns of basalt used to build Nan Madol are thought to have been mined on Pohnpei and transported to Temwen using raft (Shutterstock)

Even if Nan Madol leaves visitors with more questions than answers, it’s hard not to be wowed by its architectural prowess. Its towering dark-maroon walls have been fashioned from columnar basalt, with blocks stacked in header and stretcher construction, where the outward-facing ends of carved stones sandwich others laid lengthwise. These facades glisten under the heavy skies (Pohnpei is one of the wettest places on Earth) as local guides bring Nan Madol to life with stories of the Saudeleur worship of eels and of turtle sacrifices. The highlight is the imperious fortification of the royal mortuary on Nandauwas islet, where the walls are stacked nearly eight metres high.

If Nan Madol can be saved from being subsumed by the mangroves that threaten its preservation, its potential to reveal more secrets about an advanced, complex civilisation could be significant. In 2019, American researchers using an airborne LiDAR survey revealed a hitherto unknown and extensive irrigation and cultivation system that likely places the Saudeleur dynasty, in terms of wealth and importance, at the very heart of Pacific Ocean power. Who knows what else this city might eventually reveal if given time?

Need to know information

Ruined city Nan Madol (Shutterstock)

Ruined city Nan Madol (Shutterstock)

Location: Temwen Island lies off the shores of Pohnpei, one of the larger islands in the Federated States of Micronesia.

Getting there: Reaching Pohnpei requires determination and deep pockets. Expect to be on a plane for 20 hours if flying from the UK. One option is via Tokyo, connecting to Guam on another four-hour flight. Thereafter, United Airlines offer an ‘island-hopping’ service that connects to Pohnpei, a further 3–4 hours away, from Guam for around £500 return.

Getting around: Nan Madol can be approached by taxi, rental car or boat from Kolonia or Palikir, but do take a guide as the ruins are challenging to both interpret and navigate. Local accommodation should help arrange tours and transportation.

When to go: There’s no particular peak season because Pohnpei is pretty hot (27ºC) and wet year-round.

Accommodation: AirBnB has now arrived on the islands of Micronesia; otherwise, Mangrove Bay Hotel has nice doubles with sea views from around £97 per night.

Further information: Visit

Related Articles