In the finale of its Moon Monday series, Kurzgesagt tells us all about the largest of Neptune's moons, Triton.
Triton wasn't always a moon, and began its life as a dwarf planet that was seduced by Neptune's gravitational pull and now orbits the solar system's eighth planet. Triton is huge, the seventh-largest moon in the solar system and bigger than all known smaller moons combined. It's also one of the four objects in the solar system that's known to be geologically active.
The video teaches you all about Triton, and explains a few theories as to how Triton was pulled into the Neptune system.