Polynesia’s largest ancient structure is the intriguing, pyramidal Pulemelei Mound (sometimes called Tia Seu Ancient Mound). Constructed sometime between AD 1100 and 1400, it measures 65m by 60m at its base and rises to a height of more than 12m. Its original purpose continues to baffle experts. It’s a stirring place, with views from its stony summit to the ocean and into thick rainforest. The surrounding area is presumably covered in important archaeological finds but, for now, the jungle hides its secrets.

　　It's very difficult to visit the mound as it’s located on disputed land. There’s no signage or upkeep: the path to the site and the mound itself are very overgrown. Guides often refuse to take people here because they worry that someone who has an ambiguous claim to the land may hassle them into handing over an exorbitant fee, or worse, just kick them off. That said, it may be possible to pick up a guide; ask at the fale at nearby Afu-A-Au Falls.

　　If you want to try it sans-guide, head down the road flanked by iron poles that starts about 300m beyond the iron-girder bridge on the opposite side of the river from Afu-A-Au Falls (no sign). You’ll soon reach a rocky ford over a stream (impassable without a good 4WD). Park here, cross the creek at the bend and enter an overgrown track between two poles. The track follows an old road bordered by stone walls, then continues up a fern-filled path to the mound. The walk takes about an hour each way: you'll need water and sturdy shoes.

　　This is a very secluded area – women especially should not walk alone, and don’t leave any valuables in your car.