By comparison, the temperature of crustal fluids can reach 400 degrees C at hydrothermal vents in the Mid-Atlantic Ridge, where tectonic plates are diverging and new oceanic crust is being formed.

The map depicts the mid-ocean ridge zigzagging its way around the world. It looks like if you ran your fingers over the paper, you'd be able to feel where it rises and falls.

The Mid-Atlantic Ridge, a massive underwater volcanic mountain range, runs directly through Iceland, making it one of the few places in the world where this geological feature is visible on land.