Cruise line officials are trying to figure out how two passengers managed to fall at least 50 feet from a ship's balcony into the Gulf of Mexico Sunday, where they were rescued hours later.
"You cannot just fall off a ship," said Princess Lines' spokeswoman Julie Benson, describing the occurrence as "extremely rare ... this hasn't happened to Princess, that I can recall."
The 22-year-old man and 20-year-old woman -- who have not been identified publicly other than as Americans -- fell at about 1:30 a.m., 150 miles from Galveston, Benson said.
They were recovering Sunday with minor injuries in the medical center aboard the Grand Princess, a spokeswoman for Princess Cruises told CNN.
"They're being watched and treated for their injuries," which include hypothermia from the 71-degree water, Benson said.