What others have mentioned above, there is a lot of work with luminosity masks and dodging and burning.
It reminds me a little of my own work.
I intentionally took this picture very underexposed to avoid overexposing of very bright gap between darker clouds and a block of flats. The girl with the bicycle, trees and grass was accordingly very dark. With the use of luminosity masks and lot of dodging and burning I managed to direct the viewer’s attention to a diffusely illuminated girl with a bicycle:
Fahradmädchen by Boris Hajdukovic, auf Flickr
Similar to this picture; I used the same methods to brighten up the front of the houses and the street:
Franz Mehlhose Café by Boris Hajdukovic, auf Flickr
To learn how to use luminosity masks in GIMP I highly recommend the tutorial by Pat David:
Getting Around in GIMP - Luminosity Masks