The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

An impressive cliff, up to 4000 m high, is located in the eastern part of Echus Chasma. Gigantic water falls may once have plunged over these cliffs on to the valley floor. The remarkably smooth valley floor was later flooded by basaltic lava.