These are the reflections of light inside Cologne Cathedral (Germany) as the sun is shining through the famous stained glass window by artist Gerhard Richter. In 2007, Richter designed a window in the facade of the south transept of Cologne Cathedral. He applied a pattern comprising 72 different shades of colored squares. The window consists of 11.263 mouth-blown glass squares.
Nothing in these shots is photoshopped, the colors look exactly as you see it.
If you want to visit Cologne Cathedral, make sure it is a sunny day, so you can experience this light spectacle.