Johannesburg was founded after the discovery of gold on the Witwatersrand in 1886, and grew within a decade to a city of more than 100,000 inhabitants. Although the city's own mines have long since been abandoned as ores ran out and new deposits were found elsewhere, it is still known in the Zulu language as eGoli, that is, the "place of gold". The "gold crescent" (roughly 120km long by 25km wide) around which Johannesburg grew is the source of more than half the mined gold in the world today. The mines produced tall "mine dumps" or man made mountains. These are what remains from the ore removed from the mines after the gold was extracted. The earlier of these mine dumps still contain some gold. The mine dumps have been "re-mined" to extract further gold through modern more efficient recovery techniques. A lobby formed to prevent the loss of the last of Johannesburg's last mine dumps as these are part of the city's character.
Although it was a prosperous city throughout the 20th century, in the 1990s Johannesburg was affected by urban blight, as millions of poor, mostly black, people who had been kept out artificially by the policy of Apartheid, moved into the city from surrounding black townships such as Soweto. Crime levels soared and non-payment of rent led to apartment buildings being abandoned by landlords, especially in the high-density areas such as Hillbrow. Many leading corporations and institutions, including the Johannesburg Securities Exchange, moved their headquarters to the northern suburb of Sandton. Reviving the city centre is one of the main aims of the municipal government of Johannesburg.
It is not known for certain who the "Johannes" (Afrikaans for "John") was after whom the city was named. Several candidates have been put forward over the years.