Nearly 19 miles from the nearest town, a monolithic structure called the Buzludzha Monument adorns the mountains of Bulgaria.
Surrounded by nothing but steep hills and clouds, this bizarre monument looks completely out of place with the scenic background - almost as if a spaceship had landed on the top of a cliff.
Photographer Romain Veillon got an inside glimpse of the structure and took several photographs of the building.
Check out what the structure was for, and what it looks like today: