A candidate landing site for ESA’s ExoMars 2020 mission is the billion years old landscape in Mawrth Vallis.
Video: "Flight over Mawrth Vallis" from 2016 [2:36 min]
Copyright: ESA/DLR/FU Berlin (CC BY-SA 3.0 IGO)
Mawrth Vallis is situated at the boundary of the southern highlands to the northern lowlands on Mars and has a length of 600 km and a depth of up to 2 km.
Link to press release: Flight over Mawrth Vallis (Dec 08, 2016)