Final answer:
Nan Madol in Pohnpei, Micronesia, is known for its megalithic architecture, consisting of massive basalt structures on man-made islands.
Step-by-step explanation:
The Nan Madol site in Pohnpei, Micronesia, is characterized by megalithic architecture. This impressive archaeological site was built between 1200 and 1600 AD and consists of massive and heavy basalt structures placed on artificial islands. Nan Madol showcases a network of canals, which, according to oral histories, were constructed to allow marine life like eels to enter the city. These canals may also provide insight into how the megalithic structures were transported and positioned. Due to the sheer size and weight of the basalt and coral used in the construction, understanding the engineering techniques employed remains a significant historical mystery.