There are some really cool photos and information on the NASA website. This is a picture of the famous Berkley Pit Mine in Butte.

Butte was a boomtown due to the mining opportunities there. This mine was open from 1955-1982. There have been all kinds of issues as far as clean up. The Berkeley Pit is one of the largest clean up sites that is contaminated with hazardous materials and pollutants.

The pit is currently a tourist attraction. You can pay to go out on the viewing platform. As you can see in the photo it is a big mine if it is that large from space...