The largest frozen zoo is inside California's San Diego Zoo Institute for Conservation Research. Here, there are vacuum-sealed steel tanks that contain 10,000 individual samples. These samples represent about 1,000 species and subspecies—including one extinct species. The mission of the San Diego Frozen Zoo (and, likely, all the others around the world) is to preserve "a legacy of life on Earth." Frozen zoos could bring back animals from extinction (if they really wanted to). But from a less sensational angle, these zoos are working to conserve the species, big and small, we have here now. For example, they've helped breed the world's first caracal kittens, which you can watch in the video below. Seriously, watch the video. You need to see those kittens.