A 13,800-year-old slab of rock found in an archaeological site in Spain has engravings that are thought to be some of the earliest depictions of a hunter-gatherer campsite.
How stress affects your brain
Introducing Homo Naledi, the newest member to humanity’s family tree.
The number of trees per person in the world. There’s an estimated 3.04 trillion trees on the entire planet.
Pictured: Adansonia grandidieri, Madagascar
How much of stuff (or lack of stuff) will kill you.