A strange "sonar anomaly" had NOAA explorers diving off the coast of North Carolina on Wednesday, hoping for an explanation.
NOAA has not been afraid to notch up suspense about the area, noting it could be "an archaeology site, a geological formation or otherwise."
It's anybody's guess what "otherwise" means, but UFO enthusiasts might be tingling with ideas.
The site is being called the “Big Dipper Anomaly" by the crew aboard NOAA's Okeanos Explorer, which launched a remotely operated vehicle in the area at 8:30 a.m. Wednesday.
Experts believed the anomaly might be a shipwreck, but were leaning toward "a geological formation with biological communities and other debris" later in the day, according to TV station WTKR in Virginia. The site yielded "many fish species and other fauna," NOAA said in a tweet.
The location of the anomaly is being kept confidential.
North Carolina's coast is known as the "Graveyard of the Atlantic," due to the large number of ships that have sunk in the region. The vessels range from pirate ships to Civil War blockade runners to German U-boats sunk during World War II.
The Okeanos Explorer expedition set out in late May to gather data on "unknown and poorly understood deep water areas of the Southeastern United States."
"Teams will work together to map the seafloor and observe many of these sites for the first time," NOAA says on its Okeanos Explorer website.
The areas being explored are between 820 and 13,124 feet down and include plateaus, ridges and "submarine canyons offshore of North Carolina."