Earthen Mounds, Cambodia

In several of Cambodia's ancient towns, researchers in 2016 found enigmatic clay mounds in the form of domes. These grid-patterned mounds, which archaeologists refer to as dome fields, are thought to be about 1,000 years old. Experts also found mounds in other geometric shapes, like spirals, in addition to the dome fields. These mysterious buildings had lain undiscovered in Cambodia's dense jungles for many years. These dome fields weren't discovered by scientists until they used low-flying helicopters to scan the jungle with lasers.

Scientists are most perplexed by the function of these enigmatic structures. The purpose of the dome fields and why the ancient Khmer Empire created them all throughout Cambodia are still unknown to experts. However, scientists are aware of one thing in common with these mysterious clay mounds: they were all constructed close to Cambodian temples. These clay mounds will someday reveal their secret to archaeologists with the aid of contemporary technology, but for the time being they "remain among the most perplexing characteristics of Khmer landscape archaeology".