Today, the former Homestake Gold Mine, a 300-mile (480-kilometer) tunnel system carved inside the mountains, houses the Sanford Underground Research Facility, where scientists study particle ...

A sign welcomes visitors to a lab 4,850 feet beneath the earth, Wednesday, May 30, 2012, where the Sanford Underground Research Facility inside the now-shuttered Homestake Gold Mine in Lead, S.D ...

Today, the former Homestake Gold Mine, a 300-mile (480-kilometer) tunnel system carved inside the mountains, houses the Sanford Underground Research Facility, where scientists study particle physics ...