 Welcome to our hands update, this is your week in Navy history. On April 10th, 1963, 129 shipmates perished as USS Thresher was lost off the coast of Cape Cod, Massachusetts while performing diving tests, making this the U.S.'s greatest single submarine disaster in terms of loss of life. On April 4th, 1949, the North Atlantic Treaty was signed in Washington, D.C., establishing NATO. NATO was the first peacetime military alliance the U.S. entered into outside the Western Hemisphere. April 6th, 1917, following the sinking of U.S. merchant vessels by German U-boats, the U.S. entered World War I. The first American ships arrived in Europe within a week, marking a decisive end to U.S. neutrality. To learn more about Navy history, visit the Naval History and Heritage Commence website.