Simply begin typing or use the editing tools above to add to
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of Mars ...in a drawing of Mars of that date by Christiaan
Huygens. It is an extensive regional slope elongated north to
south that drops 4 km (2.5 miles) from its western boundary
(Aeria) to its eastern edge ( Isidis). Assiduously observed for
more than a century because of its seasonal and long-term
variability, especially near its eastern boundary, Syrtis Major
was first considered a shallow sea. Later... What made you want
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