At the beginning of 1966, the number of U.S. military personnel in South Vietnam totaled 184,314.
 South Vietnamese military forces totaled 514,000 including the army (ARVN) and the Regional Force and Popular Force (the "Ruff-Puffs") militias.
 The North Vietnamese Army (PAVN) numbered 400,000, most still in North Vietnam.
 50,000 North Vietnamese cadre and soldiers infiltrated South Vietnam during 1965.
 Group 559, charged with transporting supplies down the Ho Chi Minh Trail to supply communist troops in both South Vietnam and Laos, numbered 24,400 personnel.
Robert Strange McNamara (June 9, 1916 – July 6, 2009) was an American business executive and the eighth Secretary of Defense, serving from 1961 to 1968 under Presidents John F. Kennedy and Lyndon B. Johnson.
 He played a major role in escalating the United States involvement in the Vietnam War.
 McNamara was responsible for the institution of systems analysis in public policy, which developed into the discipline known today as policy analysis.
North Vietnam supported the Pathet Lao to fight against the Kingdom of Laos between 1958–1959.
 Control over Laos allowed for the eventual construction of the Ho Chi Minh Trail that would serve as the main supply route (MSR) for enhanced NLF (the National Liberation Front, the Vietcong) and NVA (North Vietnamese Army) activities in the Republic of Vietnam.
 As such, the support for Pathet Lao to fight against Kingdom of Laos by North Vietnam would prove decisive in the eventual communist victory over South Vietnam in 1975 as the South Vietnamese and American forces could have prevented any NVA and NLF deployment and resupply if these only happened over the 17th Parallel, also known as the Demilitarized Zone (DMZ), a narrow strip of land between North and South Vietnam that was closely guarded by both sides.
 It also helped the Pathet Lao win the Kingdom of Laos, although the Kingdom of Laos had American support.
Operation "Tiger Hound" was a covert U.S. 2nd Air Division, later Seventh Air Force and U.S. Navy Task Force 77 aerial interdiction campaign conducted in southeastern Laos from 5 December 1965 till 11 November 1968, during the Vietnam War.
 The purpose of the operation was to interdict the flow of People's Army of Vietnam (PAVN) supplies on the Ho Chi Minh Trail (the Truong Son Strategic Supply Route to the North Vietnamese) from the Democratic Republic of Vietnam (North Vietnam), through southeastern Laos, and into the northern provinces of the Republic of Vietnam (South Vietnam).
 The missions were originally controlled by the 2d Air Division until that headquarters was superseded by the Seventh Air Force on 1 April 1966.
The Hồ Chí Minh trail (also known in Vietnam as the "Trường Sơn trail") was a logistical system that ran from the Democratic Republic of Vietnam (North Vietnam) to the Republic of Vietnam (South Vietnam) through the kingdoms of Laos and Cambodia.
 The system provided support, in the form of manpower and materiel, to the National Front for the Liberation of South Vietnam (called the Viet Cong or "VC" by its opponents) and the People's Army of Vietnam (PAVN), or North Vietnamese Army, during the Vietnam War.
The McNamara–Taylor mission was a 10-day fact-finding expedition to South Vietnam in September 1963 by the Kennedy administration to review progress in the battle by the Army of the Republic of Vietnam and its American advisers against the communist insurgency of the National Liberation Front of South Vietnam.
 The mission was led by US Secretary of Defense Robert McNamara and General Maxwell D. Taylor, the Chairman of the Joint Chiefs of Staff.
The McNamara Line was an operational strategy employed by the United States in 1966–1968 during the Vietnam War to prevent infiltration of South Vietnam by NVA forces from North Vietnam and Laos.
 The McNamara Line ran across South Vietnam from the South China Sea to the Laotian border along the Vietnamese Demilitarized Zone (DMZ).
 The eastern part included fortified field segments with Khe Sanh as linchpin, along with stretches, where roads and trails were guarded by the high-tech acoustic and heat-detecting sensors on the ground and interdicted from the air.
 A sophisticated electronic surveillance was backed with assorted types of mines, including so-called gravel mines, and troops at choke points.
 Named "the barrier system" by Robert McNamara, it was one of the key elements, along with gradual aerial bombing, of his war strategy in Vietnam.
Project Dye Marker was a cover name for a strong point/obstacle component of the electronic anti-infiltration barrier system in South Vietnam known as "McNamara Line" during the Vietnam War, which aimed to create an alternative to the US bombing of North Vietnam.
 The fortifications were partially constructed by the American forces in 1967-1968 along the eastern portion of the demilitarized zone.
 An effective anti-infiltration barrier, running across South Vietnam deep into Laos, was a grand vision of the US Secretary of Defence Robert McNamara, who feared that escalation of bombing can bring greater Chinese involvement, and a vital component of his operational strategy.
 It was an enormous multimillion project, which was nicknamed in the media as the Great Wall of Vietnam, McNamara's Wall, McNamara Barrier, Electric Fence, and Alarm Belt.
Operation Lam Son 719 (Vietnamese: "Chiến dịch Lam Sơn 719 or Chiến dịch đường 9 – Nam Lào" ) was a limited-objective offensive campaign conducted in the southeastern portion of the Kingdom of Laos.
 The campaign was carried out by the armed forces of the Republic of Vietnam (South Vietnam) between 8 February and 25 March 1971, during the Vietnam War.
 The United States provided logistical, aerial, and artillery support to the operation, but its ground forces were prohibited by law from entering Laotian territory.
 The objective of the campaign was the disruption of a possible future offensive by the People's Army of Vietnam (PAVN), whose logistical system within Laos was known as the Ho Chi Minh Trail (the Truong Son Road to North Vietnam).
Rhinoceros sondaicus annamiticus is an extinct subspecies of "Rhinoceros sondaicus", that lived in Vietnam, Laos, Cambodia, Thailand and Malaysia.
 The term Annamiticus derives from the Annamite name of the Indochinese Mountains in Indochina, part of the distribution of this species, also known as the Javanese Javan rhinoceros or simply Vietnamese rhinoceros for Vietnam.
 Only this species, the Stieng called them Pai-mhai once lived across South China, Vietnam, Cambodia, Laos, Thailand, and Malaysia.
 The subspecific annamiticus is derived from the Annamite Mountain Range in Southeast Asia, part of this subspecies' range.
 In 2006, a single population, estimated at fewer than 12 remaining rhinos, lived in an area of lowland forest in the Cat Tien National Park in Vietnam.
 Genetic analysis suggested this subspecies and the Indonesian Javan rhinoceros last shared a common ancestor between 300,000 and 2 million years ago.
 The last individual of this population was shot by a poacher in 2010.

Question: An effective anti-infiltration barrier, running across South Vietnam deep into Laos, was a grand vision of the US Secretary of Defence who was born in which year ?
Answer: 1916