Crews clearing the site of the 2001 World Trade Center terrorist attacks in New York City found a ship believed to date back to the 1700s.

Archaeologists said the ship, a 30-foot wood-hulled vessel buried about 20 to 30 feet below the ground, was probably used as filler along with other debris to extend lower Manhattan into the Hudson River, according to the New York Times.

Archaeologists also found a 100-pound anchor near the ship, but could not confirm if it belonged to the ship, according to reports.