An American magazine, "Imaging Notes", recently published satellite photos, taken by commercial satellites, showing heretofore secret Chinese military installations. Of most interest were the coastal tunnels for Chinese submarines to operate from. Such tunnels were long rumored, and their existence denied by the Chinese. But there they are. An excellent way for subs to avoid air attack.
The companies that provide commercial satellite photos will usually abide by requests from nations to not distribute photos of certain areas, or not provide high resolution photos of some areas. But as more operators are out there selling their photos, competitive pressures have made it possible to get just about whatever you want. It's a whole new world, and anyone can get a detailed satellite view of it.