The USS Pueblo, a U.S. naval research ship that was famously captured by North Korea in 1968, has disappeared from its mooring in downtown Pyongyang.

Converted by North Korean authorities into a tourist spot to showcase its citizens the threat posed by the U.S., the disappearance of the vessel has many observers scratching their heads to explain what may have happened.

North Korea tour operator Koryo Tours today reported the disappearance of the boat on their Facebook page following the return of staff from a recent trip.

While unable to photograph the disappearance of what North Korea has long alleged