486958 Arrokoth is a “cold classical” Kuiper Belt Object that on 1 January 2019 became the most distant object ever visited by a spacecraft — NASA’s New Horizons flew within 3,500 km at 6.6 billion km from Earth. Arrokoth is a contact binary: two distinct lobes (nicknamed Ultima and Thule) that gently merged together in the Solar System’s earliest days. Its pristine surface has been preserved at ~40 K for 4.5 billion years, making it the best sample we have of the primordial Solar System.