Humanity finds a mysterious object buried beneath the lunar surface and sets off to find its origins with the help of HAL 9000, the world's most advanced super computer.
Thanks to the altitude and inclination of the International Space Station's orbit, that's exactly how many sunsets astronauts living aboard the orbital lab get to experience. In this photo ...
National Geographic's enterprising photographers have helped readers explore and learn about our beautiful world through their images for more than a century. Here is their best work from the past ...