With a history as old as the United States itself, there is no doubt that there are plenty of ghost stories from the U.S. military’s almost 246 active years to keep you up at night. From watery graves to haunted houses, sites of battles and ghoulish residences of military leaders long gone are ripe for spiritual and sinister happenings.

Here are six ghost stories that’ll chill you to your bones.

1. The USS Hornet’s ghostly inhabitants

The USS Hornet and her crew served in World War II and the Vietnam War, achieving numerous awards for service and operations. She also was the prime recovery ship for the Apollo 11 and 12 missions.

During her active years, about 300 crew members died from accidents and suicides. Visitors to the ship’s permanent location in San Francisco report hearing voices and seeing apparitions of soldiers. Electronic equipment is also known to go haywire on board. Now the host of ghost tours, the USS Hornet holds the title of the most haunted ship in America.

2. The watery grave of the USS Arizona

Next on our list is another haunted WWII-era Navy ship, the USS Arizona. When the Japanese attacked Pearl Harbor on Dec. 7, 1941, the Arizona became a mass tomb for the 1,102 that perished with her. She serves as an underwater graveyard and memorial to those that died during the tragic event. However, many believe that the dead did not go in peace and still haunt the area.

Today, officers blame a ghost called “Charley” for many of the eerie happenings near the USS Arizona. This famous apparition is reportedly harmless, only turning on water faucets and causing heavy doors to swing open and closed. Another ghost, however, inspires more fear. One of the sailors who abandoned his post during the bombings allegedly haunts the deck of the ship at low tide, inspiring fear and sadness in visitors to the memorial.