<p>Valles Marineris is the largest canyon in the Solar System, and if placed on Earth, it would stretch from Los Angeles to Washington, DC. 
</p><p>NASA/JPL/University of Arizona (261 km above the surface, less than 1 km top to bottom and north is to the right.)
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<a rel="nofollow" class="external text" href="https://www.uahirise.org/ESP_025653_1730">www.uahirise.org/ESP_025653_1730</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/71688597@N05">UAHiRISE (NASA)</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/uahirise-mars/46306435295/">Possible Clay Deposit in Valles Marineris</a>