Divers have discovered a Nazi U-boat submerged inside a partially destroyed submarine pen near Kiel, city officials said Friday.

Several months ago, longtime residents told city officials they recalled there had been a submarine inside the giant concrete U-boat bunker, and divers were hired to search for the vessel earlier this month.Allied warplanes heavily bombed U-boat pens in northern Germany during World War II.

The submarine pen, on the east side of the Baltic Sea inlet where Kiel is located, was originally 198 feet wide and 561 feet long, city officials said.

Some people want the pen preserved as a memorial, but city planners want to clear the area to develop the harbor.