What are hot springs?
Earth's Secret Spa
What are hot springs?
You're hiking up a cold mountain trail when you smell something strange — like eggs left in the sun. Around the bend, steam rises from a pool of water, and people are sitting in it, smiling. Wait. The ground is heating water? How does that even work?
Deep under your feet, the Earth is hot. Not warm — hot like an oven that's been on for four billion years. The deeper you go, the hotter it gets. Dig down just two miles and you'd hit rock hot enough to boil water instantly.
