Which mission was the first to land on Mars successfully?

Viking 1 became the first spacecraft to land successfully on Mars on 20 July 1976. It was part of NASA’s Viking program, which included an orbiter and a lander. The mission sent back the first long-term surface images and conducted experiments searching for signs of life. Its success followed several earlier failed attempts by both the United States and the Soviet Union. Viking 1 remains one of the most important milestones in planetary exploration.