Tiny, faraway Pluto was first spied in 1930. This icy world is one of thousands of rocky bodies that make up the Kuiper Belt, a ring that circles our solar system beyond Neptune. Until recently, the most powerful telescopes on Earth and in space could only capture blurry impressions of Pluto and its moons. But in 2015, New Horizons became the first spacecraft to visit the Pluto system, returning detailed images and data that will bring our distant neighbor’s surface, atmosphere, and internal composition into focus for the first time.