They might look like spaceships from a retro sci-fi movie, but these strange shapes hovering above the mountains in Patagonia are of earthly origin. These are lenticular clouds, named after their lens-like shape. They form near hills and mountains where moist air is pushed up and over the peaks, cooling as it rises and condensing into water droplets. As wind blows over the mountains it can create a series of waves in the air, and these unusual clouds form in the crest of those waves.