Second in size only to the Vredefort Dome, the Sudbury Basin is a 40-mile-long, 16-mile-wide, 9-mile-deep crater caused by a giant meteorite that struck Earth about 1.85 billion years ago. Located in Greater Sudbury, Ontario, the crater is actually home to about 162,000 people. In 1891, the Canadian Copper Company began mining copper from the basin, but it was soon discovered that the crater also contained nickel, which is much more valuable, so the miners changed course. Today, the International Nickel Company operates out of the basin and mines about 10 percent of the world's nickel supply from the site.
Related HowStuffWorks Articles
A dark matter hurricane heads toward Earth. HowStuffWorks looks at why scientists are excited.