This year we said goodbye to one of our most intrepid planetary explorers, the Opportunity rover. Take a look back at its storied 15-year mission on Mars, and how it revolutionized our understanding of not just the red planet.

El León es conocido como el Rey de la Selva. Pero fueron los tigres dientes de sable los que gobernaron las Américas en el pasado. Sus fósiles nos cuentan la vida violenta y casi humana de esta misteriosa especie.

The Greenland ice sheet, the last remnant of the Ice Age, is melting at an unprecedented rate. Today, scientists and researchers from all over the world are paying close attention to what could become a global catastrophe.

For all of human history, the Sun, our home star, has measured our days and our seasons while fueling all life on Earth. Yet it remains an enigma. NASA's Parker Probe Plus is on a mission to change that -- flying through dangerous radiation to become the closest spaceship to orbit our Sun.

Wildfires have greatly increased in size and intensity over the past few years. After record-setting conflagrations erupted in the region's prized forests, new tools using technology are being developed to help save property and lives.

Lions may be known as the kings of the jungle, but it was saber-tooth cats that ruled over the Americas. New fossil evidence is shinning a light on the violent lives of these mysterious species.