GEOLOGY

The impressive gemstone comes in at 2492 carats.

Watch an explorer share what it's like to descend into the Darvaza Gas Crater, also known as the “Gates of Hell.”

Chemical signatures from the Chicxulub asteroid’s impact—which caused a mass extinction on Earth 66 million years ago—match those of carbonaceous meteorites formed beyond Jupiter.

The nightmare scenario described in an influential 2008 study may end up being less destructive than scientists thought, but Angelenos still shouldn't get too comfortable.

The epic effort to rescue Floyd Collins was a battle between heroism and folly, selflessness and selfishness, and life and death.

There's much more to the Wyoming landmark than what you saw in ’Close Encounters of the Third Kind.’

They may not be as “precious” as diamonds or emeralds, but these scarce gems are just as valuable—if not more so.

Caves and volcanoes don’t often go hand-in-hand in our imaginations, but the second most common type of cave in the world is made from the power of volcanoes.

If you've wondered what the land underneath Antarctica's ice actually looks like, science has an answer.

In Northern Ireland, thousands of hexagonal stone columns of various heights rise out of the North Atlantic Ocean and climb up to the foot of a cliff, as if they had been placed by a massive mythical creature.

The biggest tsunami ever recorded reached 1720 feet high—which is taller than the Willis Tower in Chicago.

Many of the world’s biggest caves have been discovered just in the past few decades. Here are some of the most impressive.