The Midcontinent Rift is a giant tear that formed in what is now the U.S. Midwest 1.1 billion years ago. Nicknamed North America's "broken heart," it is filled with solidified magma and lava.

Add Yahoo as a preferred source to see more of our stories on Google. Researchers have discovered that the North American continent is slowly losing rock from its underside in a process called ...

Scientists have uncovered a massive ancient geological feature beneath the Midwestern United States — a billion-year-old rift valley that nearly split the North American continent in two. This ...

Add Yahoo as a preferred source to see more of our stories on Google. When you buy through links on our articles, Future and its syndication partners may earn a commission. An ancient slab of Earth's ...