The OES visited Alligator Mound on June 11, 2001. Alligator Mound was built around 2,000 years ago on top of a hill that is now part of the Bryn Du Woods housing development in Granville. It is one of only two effigy animal mounds in Ohio, the other being the Great Serpent Mound in Adams County. Archaeologists for many years believed Alligator Mound was built by the Hopewell culture, however, carbon dating in the late 1990s revealed that the Fort Ancient culture was most likely the constructors of the mound. Researchers believe the mound's shape actually represents an opossum, raccoon or panther rather than an alligator since alligators are not native to Ohio. Of those options, the mound most likely represents the Underwater Panther, one of the most powerful supernatural spirits of the Native Americans. Early settlers may have misunderstood the translation of this creature, deemed it an alligator and the name stuck. Alligator Mound was nearly lost to a quarrying operation in the 1840s. The owner of the quarry agreed to halt operations, but the land was then turned to a pasture and remained that way for many years. It wasn't until the 1970s-80s that interest in preserving the effigy mound came about. Alligator Mound was placed on the National Register of Historic Places in 1971 and is now preserved as a small park.