Short answers, pulled from the story.
Johannesburg was founded in 1886, following the discovery of the main Witwatersrand gold reef by Jan Gerritse Bantjes in June 1884 on the farm Vogelstruisfontein. The city was established on what had been farmland specifically because of the rich gold deposits found along the Witwatersrand hills.
The precise origin of the name Johannesburg is disputed and the records were lost. Several men named Johannes were involved in the city's early history, including Christian Johannes Joubert and Johann Rissik, both surveyors who helped lay out the city, as well as Johannes Meyer, the first government official in the area, and Paul Kruger, president of the South African Republic from 1883 to 1900. The name was first officially used on the 3rd of October 1886.
Johannesburg was central to anti-apartheid resistance. On the 11th of July 1963, police raided a house in the suburb of Rivonia and arrested nine ANC members including Nelson Mandela, leading to the famous Rivonia Trial. The city's township of Soweto became the epicenter of the 1976 Soweto Uprising, in which about 575 people were killed after police fired on student protesters. Both Nelson Mandela and Desmond Tutu lived in Soweto.
Soweto, whose name stands for South-Western Townships, was a township built by the apartheid government in the 1950s and early 1960s to house black workers employed in Johannesburg's gold mines. It was designated a "blacks only" city until 1994 and was intended to hold 50,000 people, but grew to roughly equal Johannesburg's own population by 1989. It was home to Nelson Mandela and Desmond Tutu and was the site of the 1976 Soweto Uprising.
The City of Johannesburg itself has a population of 5,538,596, while the City of Johannesburg Metropolitan Municipality has a population of 6,599,190, making it one of the 100 largest urban areas in the world. Broader estimates of the urban agglomeration range as high as 15,026,000 as of 2025.
Johannesburg hosted the 2010 FIFA World Cup final at FNB Stadium, the largest stadium in Africa, and the closing ceremony of that World Cup marked Nelson Mandela's final public appearance. The city also hosted the 2015 African Union Summit, the 10th BRICS Summit in 2018, the 15th BRICS Summit in 2023, and the 2025 G20 Johannesburg Summit, which was the first G20 Presidency held by an African country.