We took a boat tour in the Ha Long Bay in the Gulf of Tonkin.

A UNESCO Heritage Site, civilization in this area dates back 25,000 years.

Fifty years ago, however, this area provided the spark that started the fire.

The Gulf of Tonkin Incident (or the USS Maddox Incident) is the name given to two separate confrontations involving North Vietnam and the United States in the waters of the Gulf of Tonkin.

On August 2, 1964, the destroyer USS Maddox, while performing a signals intelligence patrol, engaged three North Vietnamese Navy torpedo boats of the 135th Torpedo Squadron. A sea battle resulted, in which the Maddox expended over two hundred and eighty 3-inch and 5-inch shells, and in which four USN F-8 Crusader jet fighter bombers strafed the torpedo boats. One US aircraft was damaged, one 14.5 mm round hit the destroyer, three North Vietnamese torpedo boats were damaged, and four North Vietnamese sailors were killed and six were wounded; there were no U.S. casualties.

It was originally claimed by the U.S. National Security Agency that the second Tonkin Gulf incident occurred on August 4, 1964, as another sea battle, but instead may have involved "Tonkin Ghosts" (false radar images) and not actual torpedo boat attacks.

The outcome of these two incidents was the passage by Congress of the Gulf of Tonkin Resolution, which granted President Lyndon B. Johnson the authority to assist any Southeast Asian country whose government was considered to be jeopardized by "communist aggression." The resolution served as Johnson's legal justification for deploying U.S. conventional forces and the commencement of open warfare against North Vietnam.

US Defense Secretary Robert McNamara failed to inform US President Lyndon B. Johnson that the U.S. naval task group commander in the Tonkin Gulf, Captain John J. Herrick, had changed his mind about the alleged North Vietnamese torpedo attack on U.S. warships he had reported earlier that day.

By early afternoon of 4 August, Washington time, Herrick had reported to the Commander in Chief Pacific in Honolulu that "freak weather effects" on the ship’s radar had made such an attack questionable. In fact, Herrick was now saying, in a message sent at 1:27 pm Washington time, that no North Vietnamese patrol boats had actually been sighted. Herrick now proposed a "complete evaluation before any further action taken."

McNamara later testified that he had read the message after his return to the Pentagon that afternoon. But he did not immediately call Johnson to tell him that the whole premise of his decision at lunch to approve McNamara’s recommendation for retaliatory air strikes against North Vietnam was now highly questionable. Had Johnson been accurately informed about the Herrick message, he might have demanded fuller information before proceeding with a broadening of the war. Johnson had fended off proposals from McNamara and other advisers for a policy of bombing the North on four separate occasions since becoming President.

In 1965, President Johnson commented privately: "For all I know, our Navy was shooting at whales out there."

In 1981, Captain Herrick and journalist Robert Scheer re-examined Herrick's ship's log and determined that the first torpedo report from August 4, which Herrick had maintained had occurred—the "apparent ambush"—was in fact unfounded.

In the 2003 documentary "The Fog of War", the former Secretary of Defense Robert S. McNamara admitted that the Aug 4 attack never happened.