The U.S. withdrawal left the South Vietnamese with a well equipped but poorly led army unable to contain the 1974-75 Communist assault that ended in the capture of Saigon.

The Paris Peace Accord finally brought an end to the Vietnam War, and the last U.S. Soldiers left Vietnam on March 29th, 1973. Two years later, Saigon fell to the North Vietnamese Army. Vietnam was reunited.

The air war against the north intensifies as fighting in the south escalates. The U.S. targets North Vietnamese transport and supply routes (some of them in Laos and Cambodia), culminating in the so-called Christmas bombings of Hanoi and Haiphong in December, 1973.

The first of two programs on American bombing during the war, concentrates on the campaign prior to 1965, and examines how the Communists responded to U.S. air superiority.

In early 1968, American and allied forces fought the North Vietnamese Army in one of the most dramatic battles of the Vietnam War. For 77 days, two powerful NVA Divisions laid siege to the U.S. Marine Corps base at Khe Sahn.

Unlike the two world wars and the many before, the conflict in Vietnam was void of a so-called front line. Battles were fought in pockets of resistance, with troops dropped in by helicopter. What did exist was the section of the country dividing the North from the South known as the DMZ (De-Militarized Zone). This was often an arena of heavy combat, and Battlefield Vietnam: War on the DMZ highlights such furious fighting as "Operation Hastings" and "Operation Prairie."

Viet Cong guerrillas, backed by the North Vietnamese Army, staged a massive offensive against major cities and U.S. bases in January 1968, during the Tet holiday.

Viet Cong incursions in 1967 prompt the U.S. to reinforce key southern bases, unaware that the North Vietnamese were planning an all-out assault for early 1968. Included: combat footage; comments from veterans.

Expanding its presence in 1966, the U.S. Army sets up patrols in the south to draw out Viet Cong guerrillas, but can't force a decisive battle. Included: veterans recall missions to uncover Viet Cong bases; the political climate in Saigon.

While the method of "search and destroy" is the ultimate goal for any armed conflict, it developed a new face in Southeast Asia during the Vietnam War. With the absence of an actual front line, the North circumvented skirmishes by entering neighboring Cambodia, only to reappear within striking distance of the South stronghold of Saigon. With such bold initiative, the American contingent retaliated with heavily armed helicopter gunships from the U.S. First Air Cavalry Division, thus introducing the world's first helicopter-based military formation at the battle of the La Drang Valley.

What starts as a ripple becomes a wave, and with the United States involvement in Vietnam, it began as a contingent of U.S. "military advisors" after the attack at Dien Bien Phu. From there it turned into "non-official combat missions," and finally, after an unprovoked torpedo attack by a North Vietnamese patrol boat against the unsuspecting U.S. destroyer Maddox, it became "The Undeclared War."

In 1953 the French and Viet Minh forces had been at war for seven years. The climactic encounter of the war occurred at Dien Bien Phu, a small hamlet in northwestern Vietnam, in a battle that neither side could afford to lose