In "The Mars Mystery," Graham Hancock writes, "In frames sent back by Mariner 9 and Viking 1, strangely familiar objects can be seen that have been interpreted by some scientists not only as signs of life but as evidence that advanced intelligent life must once have been present on Mars.
......The earliest anomalous images were acquired during 1972 and show an area of Mars known as the Elysium Quadrangle. At first little attention was paid to these images. Then in 1974 a brief notice appeared in the scientific journal "Icarus." Written by Mack Gipson, Jr., and Victor K. Ablordeppy, the article reported:
"Triangular and pyramid-like structures have been observed on the Martian surface. Located in the east central portion of the Elysium Quadrangle, these features are visible on the Mariner photographs, B frames MTVS 4205-3 DAS 07794853 and MTVS 4296-24 DAS 12985882. The structures cast triangular and polygonal shadows. Steep-sided volcanic cones and impact craters occur only a few kilometers away. The mean diameter of the triangular pyramidial structures at the base is approximately 3 kilometers and the mean diameter of the polygonal structures is approximately 6 kilometers."
Another Mariner photograph, frame 4205-78, quite distinctly shows four massive three-sided pyramids. These were commented on in 1977 by....astronomer Carl Sagan. "The largest," he wrote, "are 3 kilometers across at the base and 1 kilometer high --- much larger than the pyramids of Sumer, Egypt, or Mexico on Earth. They seem to be eroded and ancient and are, PERHAPS, only small mountains, sandblasted for ages. But they warrant, I think, a careful look."
What is particularly notable about the 4 structures captured in this latter frame is that they appear to have been set out on the Martian surface in a definite pattern or alignment very like pyramids on terrestrial sites. In this they also have much in common with other Martian "pyramids" that lie in a region known as Cydonia, at approximately 40 degrees north latitude, almost halfway around the planet from Elysium."