Sketches on a stone unearthed in Marbella, Spain, are believed to be 200,000 years old, providing insight into settlers ...

For the first time on a global scale, 20 years of observations on Mars have been condensed into a single study led by ...

Humans have remodeled the Earth so profoundly that in 2000, atmospheric chemist Paul Crutzen and biologist Eugene Stoermer ...