VIDEO - Tàu Ngầm Nguyên Tử Lớn Nhất Của Hải Quân Hoa Kỳ

USS Pennsylvania is a United States Navy Ohio-class ballistic missile submarine which has been in commission since 1989. The Ohio class is a class of nuclear powered submarines used by the United States Navy. The Navy has 18 Ohio-class ballistic missile submarines and guided missile submarines.