http://en.spaceengine.org/
I am in awe. I love me some science, and thought I appreciated the size of our universe, but this has left me truly astounded. This is a simulation of the known universe using real data. You can zoom to any level - from the generated mountains of a planet, to having the entire universe in your field of view.
It's still in beta, and it is quite demanding (especially in terms of required VRam) but if you can run it, you're in for a treat.
Two large pictures below. The first is of a pink planet, the other of our humble home.