27: Rare Earth

Is there any place today that resembles the Earth 4 billion years ago?

Surprisingly, the answer is yes... ish. Today, we'll learn a secret recipe for continents, one that made the very oldest rocks on Earth and is still making the island of Iceland today.

Along the way, we'll freeze a magma chamber solid, meet some politically contentious metals, and cross a real bridge from one tectonic plate to another.