Triton

Triton, is 1,680 miles (2,700 km) across and is Neptune’s largest moon. It is the seventh largest moon in the Solar System and it is an ice moon. It also orbits the Neptune backwards, in the opposite direction that Neptune rotates and is the only large moon to do so, leading astronomers to believe that Triton is actually a captured Kuiper Belt Object that fell into orbit around Neptune at some point in our solar system’s nearly 4.7-billion-year history.

More views of Triton can be seen here.