Planet Mars was having large cities with buildings, roads and cars. The entire city areas on the map are blurred out by NASA, but this video shows what is actually behind the blurred area.
Before drawing any conclusion please take in consideration that the original images from ESA have been heavily edited and retouched before they were published.
Fact is that these structures are not the result of image compression algorithms.
What you are seeing in this video might not be the actual structures but the digital remainders of structures that are actually present in the untouched images and that ESA failed to remove adequately.