This is a cropped image directly from Nasa’s website. I adjusted the color balance, no other changes were made. You can do this yourself by downloading the image from Nasa’s web server for June 17th, 2015. Here is the link

This measures out to be 12 miles wide, and 3 miles High, which is the size of a City! Was this once a very populated planet that saw its demise and decided to protect its last remaining city with some sort of force field? Maybe this is a dome for Alien life to spy on the Earth? Either way, its not a natural formation, thats for certain. Notice the pyramid to the one side, is the pyramid the battery for powering the Dome Habitat?

Decide for yourself!