The larget outflow valley that emptied a large sea on the surface of Mars. The valley flows toward the small crater (Gusev); ca. 800 km long. Location on Mars: 21.8°S 182.7°W (https://en.wikipedia.org/wiki/Ma%CA%BCadim_Vallis).
To see with mapped water systems: https://skfb.ly/o8HtY (see also: https://www.nature.com/articles/s41586-021-03860-1, where these features were published).
Data: MOLA topography (https://tharsis.gsfc.nasa.gov/MOLA/mola.php) and THEMIS images (https://themis.asu.edu/)
Exported from QGIS (vertical exaggeration = 10).