Dao Vallis is a valley on Mars that appears to have been carved by water. It runs southwestward into Hellas Planitia, and has been identified as an outflow channel. It and its tributary, Niger Vallis, extend for about 1,200 km (750 mi).
It is named after the Thai word for star, and it was proposed as a potential landing site for the 2012 Curiosity rover of the Mars Science Laboratory mission. In the fictional 2007 Canadian miniseries Race to Mars, it is the landing site for Gagarin, the lander.
Read more about Dao Vallis: Origin