The fact that there is a one-megaton nuclear bomb sat at the bottom of the Philippines sea is very worrying. The incident is known as the 1965 Philippine Sea A-4 incident. On the 4th of November 1965, the USS Ticonderoga left the U.S. Naval Base Subic Bay, Philippines. 31 days later on the 5th December 1965, the USS Ticonderoga was on a training exercise in the Philippines sea, when an accident occurred.