Without volcanoes, life on Earth would never have begun; they are responsible for both the planet's breathable atmosphere and the oceans; mineral-rich ash from regular eruptions fertilize the land.

How wildlife adapts for survival to the seasonal shifts in the sun's intensity, from wood frogs that can freeze and thaw to Arctic wolves that thrive in the chilly darkness.

A look at how the planet's limited fresh water is distributed around the globe thanks to storms, and how animals manage in the driest habitats on Earth.

There are not five separate oceans, but one; its waters linked by powerful forces that keep them on the move.

Humans are changing our planet so rapidly, it's affecting earth's life support systems: our weather, our oceans and the living world.