Remnants of an ancient city on Mars destroyed by thermonuclear attack.
Evidence supporting this theory includes the presence of nuclear isotopes in the Martian atmosphere and the detection of a thin layer of substances such as uranium, thorium, and radioactive potassium on the surface of Mars.
The absence of craters at the sites indicates that the bombs were likely detonated above ground in an air blast, which worsens the global fallout but dampens the immediate ground impact. Conversely, if detonated on the ground, the local devastation is immense but the global impact is minimized. Regardless, these explosions were powerful enough to cause a global catastrophe and significantly alter Mars’ climate. According to Brandenburg, the nuclear attack apparently wiped out two races: the Cydonians and Utopians.
The MRO HiRISE image ESP_019103_1460 shows the “Atlantic Chaos,” and a closer examination reveals a city that was almost destroyed by the thermonuclear explosions. Amid the ruins of destroyed buildings and towering structures, a largely intact dome-shaped structure is visible (See image below.)
The remnants of this city suggest that Mars was once inhabited by intelligent species like the Cydonians and Utopians, who lived there under conditions similar to those on Earth. This also serves as evidence that far more advanced civilizations may have existed for millions of years and possessed the capability to annihilate all life on a planet using thermonuclear bombs, among other means.
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Gigapan images (zoom) of the destroyed city on Mars: