NASA's Viking 1 lander touches down on Mars and returns the first images from the planet's surface.
Hundreds of thousands of people flee Vietnam by sea after 1975; many die at sea and others are resettled, mostly in Western countries.
North Vietnamese forces enter the Independence Palace; the Republic of Vietnam surrenders, ending the Vietnam War.
NASA launches Voyager 1 to study Jupiter and Saturn; it later becomes the first human-made object to reach interstellar space.
Vietnam becomes the 149th member state of the United Nations.
Richard Nixon becomes the first US president to resign, facing likely impeachment over the Watergate scandal.
Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin sign US-brokered accords, leading to the 1979 Egypt–Israel peace treaty.