A team of researchers in the US says it has solved the mystery of how the massive and incredibly heavy red scoria hats were placed atop the select Easter Island statues, or moai, that wear them.

A team of researchers in the US says it may have solved the mystery of how the massive and incredibly heavy red scoria hats were placed atop the select Easter Island statues, or moai, that wear them, according to a Pennsylvania State University news release.  The matter has long perplexed many as the headgear measures up to 6.5 feet in diameter and weighs roughly 13 tons. The statues themselves stand up to 33 feet tall. "The best explanation for the transport of the…[hats] from the quarry is by rolling the raw material to the location of the moai…Once at the moai, the [hats] were rolled up large ramps to the top of a standing statue using a parbuckling technique," Carl P. Lipo is quoted as saying in the release.  According to the statement, "Parbuckling is a simple and efficient technique...[where]...the center of a long rope is fixed to the top of a ramp and the two trailing ends are wrapped around the cylinder to be moved. The rope ends are then brought to the top where workers pull on the ropes to move the cylinder up the ramp."  It's estimated that it would have made it possible for as few as 15 workers to "move the largest preform hats up the ramps." The team came to its conclusion by using "photogrammetry and 3-D imaging."