How did a $3 billion US Navy submarine hit an undersea mountain?

Some submariners call the USS Connecticut the luxury sports car of submarines. It's a $3 billion piece of American military hardware that's fast and outfitted with the latest electronic gadgetry only available when price is not a consideration.

But despite its high cost and sophisticated tech, the United States Navy says the Seawolf-class nuclear-powered attack sub ran smack into an undersea mountain in the Pacific on October 2.

The Connecticut is now pierside at a US Navy base on the Pacific island of Guam. The Navy says it got there -- more than 1,800 miles east of the South China Sea -- under its own power and its nuclear reactor was not harmed, although 11 of its crew of suffered minor injuries in the collision.