The Great Rift Valley also known as The Valley of the First Born is one of the most striking and interesting aspects of Barsoomian geography. It is a massive valley, at least 10 miles wide, and two miles deep. The valley floor is fertile, with forests, lakes, streams, and the red sward that is common to wet areas of Barsoom.


  • It may be tempting to compare this rift with the Valles Marineris, but Burroughs wrote of this rift before it was discovered.

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