The Huygens lander reached Titan’s surface in 2005
Titan presents unique geology for an icy satellite, mainly due to the presence of a thick atmosphere. Previous to the Cassini-Huygens mission, Titan’s surface was hidden by its hazy orange atmosphere. The Cassini spacecraft and the Huygens probe unveiled an exotic but Earthlike world in many respects. Titan was found to possess vast dune fields, equatorial mountains and even lakes and seas at the poles. Titan is the only extraterrestrial body in our Solar System to possess standing bodies of liquid on its surface and is one of only three places in the Solar System, along with Earth and Mars, which we know to possess or have possessed an active hydrologic system, albeit with methane rather than water.