A cliff, up to 4,000 m high, located in the eastern part of Echus Chasma, one of the largest water source regions on Mars, is seen in this image taken by the High-Resolution Stereo Camera (HRSC) on board ESAís Mars Express and made available July 14, 2008. Echus Chasma is the source region of Kasei Valles which extends 3,000 km to the north. The dark regions REUTERS/ESA/DLR/FU Berlin/G.Neukum/Handout. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS.