The Valley of Iss, from Gods of Mars, by Edgar Rice Burroughs. Located in Mars' south polar region, just north of the ice cap and home to a race called the Holy Therns, whom the Red martians believe to be gods. Red martians follow thr River Iss on the Voluntary Last Pilgrimage to what they believe is a land of milk and honey, but upon their arrival they are immediately set upon and devoured by plant men and 12-foot 4 armed apes. Those fortunate enough to survive are enslaved by the Holy Therns. Mars' two moons can be seen rising over the cliff Rendered in VistaPro, background done in Bryce.