Here is Cologne, as seen from across the river. The building with the two spires, seen on the left, is the Cathedral.
Here is a shot of the interior. Though the building can be dark, when the noonday sun hits it just right, it's flooded in light.
If I had to pick a single favorite, it might be this one - statues bathed in the light pouring from the stained glass window in the south transept.
