The site "A stroll through the Solar System"
This site, created by the Institut de Mécanique Céleste et de Calcul des Éphémérides de l’Observatoire de Paris (the Institute of Celestial Mechanics and Ephemeris Computation) is a veritable mine of information about the Solar System. In french and in english.
In addition to furnishing an encyclopedic and comparative view, this site is a way to explore and understand the various parts of the Solar System (planets, satellites, asteroids, comets) via the history of the various discoveries.
Among other information, it details the interplanetary space missions lists the observatories on the Earth and even in space.
This stroll, through its very detail, leads to a deeper understanding of many astronomical concepts and definitions, and so to a better understanding of each of the members of our Solar System.