This image is taken by the MRO with the Hirise camera, from a distance of 319,22 kilometers away.
At first I thought it was a flying saucer, but it looks more like a dome structure.
It's hard to tell what it is, but it does look like it's next to a docking platform, maybe it's some kind of machine or a giant metal door covered with carvings and it's seating in some kind of tunnel.
Besides the impressive dome and the rectangular block, a triangular object is sitting on top of a mountain. (Image below).
One thing is for sure these objects are not natural, whether it's man-made or alien-made.
Link original image:
MarsMoonSpacePhotoZoomClub who discovered the objects shows a detailed overview of the objects in the next two videos.
Thanks to: http://ufosightingshotspot.blogspot.com/