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.
Up until last month, there were only 14 types of pentagons that could cover a surface with no gaps or overlaps. Now there are 15. Interior designers and mathematicians are ecstatic.