The Carlton Centre is a 50-storey, 223-metre skyscraper that held the title of tallest building in Africa for over 30 years. The Top of Africa observation deck on the 50th floor is one of the most unusual viewpoints in any major city: on a clear day you can see the Magaliesberg mountains 80 kilometres away, the sprawl of the townships to the southwest, and most strikingly, the mine dumps — the vast golden tailings hills that ring the CBD and make Johannesburg unlike any other skyline on earth.
The building is in the heart of the CBD, which has seen better decades. The observation deck itself is fine — the elevator works, the viewing area is clean, and the entry fee is modest. Getting there and back should be done by Uber; walking the surrounding streets is not advisable for visitors. The contrast between the view from above (the scale of the city is genuinely impressive) and the street level below is one of the more striking things about Johannesburg.