Johannesburg, South Africa. Humans will do almost anything for gold. In fact, they will even suspend themselves 2.5 miles into the Earth – braving extreme temperatures and constant seismic activity – just to mine a 30-inch gold reef. Welcome to another day at Mponeng, the world’s deepest gold mine. It is located west of Johannesburg and takes advantage of some of the deepest and richest areas of this deposit. Each day, roughly 4,000 miners take the plunge to get to the bottom of the mine. The journey includes taking the world’s tallest elevator, which hits a top speed at 40 mph. That far into the Earth’s crust, conditions are intense. Rock walls in the Mponeng mine reach temperatures of 140°F (60°C) and humidity levels often exceed 95%. At the bottom of the world’s deepest gold mine, there is a 30-inch seam of gold called the Ventersdorp Contact Reef.