This is an impressive display of US military might. Landing craft take marines to the beach who then storm ashore.
Context
Since the 19th century France had ruled Vietnam. During the Second World War Japan had taken over Vietnam. At the end of the war the French wanted to rule Vietnam but Ho Chi Minh, who had led the resistance against the Japanese during the war, opposed this. In an underground war Ho (supported by Communist China and the USSR) eventually forced the French (supported by the USA) out in 1954. North Vietnam then became communist. South Vietnam was not communist, and was propped up by American money and troops. However, the government was corrupt and unpopular. Ho Chi Minh supported rebels in the south and by the early 1960s there was a virtual civil war in Vietnam. America poured more money and troops in and by 1965 was fully involved in a full-scale war in Vietnam. US forces pulled out in 1972 and communist North Vietnam took over the South in 1975.
Interesting or important points about the film
The overwhelming impression we get from this clip is of the scale and power of US military might. It is not hard to see why they thought that they would achieve victory against the lightly armed communist Viet Cong.