Vietnam was a French colony, so there are French buildings in Saigon.
Vietnam became a colony of Japan during the Sino-Japanese War, and in 1944 there was a famine caused by the Japanese buying up all the rice.
After the end of World War II, the war between Vietnam and France began. After World War II, the war between Vietnam and France began, dividing Vietnam into North and South like the Korean Peninsula. However, the regime in South Vietnam became corrupt. The people of South Vietnam who opposed it supported North Vietnam. The South Vietnamese army became weak, so the U.S. came to fight the war on its behalf.
When an American destroyer was attacked, the U.S. bombed North Vietnam a lot. They sprayed defoliants and massacred the farmers.
A video of a South Vietnamese police chief gunning down a suspect was shown in the US. The American people came to oppose the war. The U.S. president changed and the U.S. military withdrew from the war. And the North Vietnamese won the war.