10: The Oldest Thing on Earth

What is the oldest thing on our planet? How old is it, and where was it found?

Today, we tell the story of a worldwide, decades-long hunt for a single grain of sand. We'll journey to underground magma chambers, the sun-baked Australian Outback, and the lair of a giant shrimp.

Extra credit: Let a handful of sand run through your fingers, or go pressure-wash something.