Northern Amazonis Planitia
Google Earth > Mars Exact Location 36°42'56.43"N 150°35'13.39"W You can clearly see a bridge form top left of the picture, it measure 1000 feet. Also I see a lot of 90 degree angle shape all around this area, a lot broken pieces. There is a circular shape bottom, it look it was part of another structure now broken. The circular shape is 1500 feet long and 1000 feet wide. Draw a line in the middle of that shape you will see symmetry.