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.

The Atlantic Ocean has a toxic seaweed problem.Floating in brown islands of algae, this year’s sargassum bloom has already ...

Castillo de San Marcos National Monument is the oldest masonry fort in the US. Built in the late 17th Century, its coquina ...