Which is the second-largest asteroid?
The second-largest asteroid in the main asteroid belt is Vesta, also known as "4 Vesta". It was discovered by Heinrich Olbers in 1807. Olbers had previously discovered the largest asteroid (Ceres) and third-largest asteroid (Pallas).
Vesta is the brightest asteroid visible from Earth, and is sometimes visible with the unaided eye. Most of the time you would need binoculars or a telescope to see it.
The 2nd-largest asteroid, Vesta, photographed by the Dawn space probe.