Lech Wałęsa elected president of Poland

On this day in 1990, Lech Wałęsa—who had led Solidarity, Poland‘s first independent trade union, and had received the Nobel Prize for Peace in 1983—won Poland’s first direct presidential election by a landslide. 1990. 

South Korean President Park Geun-Hye was impeached by the National Assembly amid allegations of corruption; she left office the following year, after the country‘s Constitutional Court upheld the parliamentary decision. 2016. 

Some 10 years after the World Health Organization began a global vaccination program against smallpox, the disease was officially declared eradicated. 1979. 

The animated special A Charlie Brown Christmas, featuring characters from Charles Schulz‘s popular Peanuts comic strip, first aired on American television, and it became a holiday classic. 1965.

Tanganyika became independent, with Julius Nyerere as its first prime minister, and in 1964 the territory united with the island of Zanzibar to form Tanzania. 1961 

The world’s first traffic light was erected near Westminster Bridge in London; however, it was removed a month later after a gas leak caused one of the lights to explode. 1868. 

Revolutionary forces under the leadership of Venezuelan Antonio José de Sucre defeated the Spanish royal army at the Battle of Ayacucho. 1824.