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HiRISE 3D: The Lonely Streak
While it might look like fluid, it’s just dark material that was exposed likely by a falling boulder. It’s not too lonely as there are other streaks here, but it is the largest of them.
https://www.uahirise.org/anaglyph/ESP_073683_1645_ESP_073828_1645_RED
NASA/JPL-Caltech/UArizona
