The correct answer to this open question is the following.
Unfortunately, you forgot to attach the image. Without the image, we do not it's content. Just you.
However, although you forgot to include the image, trying to help you we did some deep research and can comment on the following.
There is an image that depicts domino figures with the names of Vietnam, Laos, China, Korea, and other south Asia countries. These domino figures are falling causing the domino effect.
What this image illustrates is "the reason for United States military involvement in Asia."
Those were the Cold War years in which the United States and the Soviet Union competed almost in everything, basically in the arms race, the space race, and the spread or containment of Communism.
These caused too many problems and tension not only between the two but to all the countries. The USSR wanted to spread Communism all over the world, while the United States tried to instill the foreign policy of containment.
This rivalry took the world to extreme scenarios as was the case of the Cuban Missiles Crisis of October 1962, when the world was on the brink of another major war.
