This picture was obtained with SNS-HDR with 3 source pictures.
This picture is a composite of 2 HDR results:
I used the "dramatic" preset in SNS-HDR to have this impressive sky on a first TIFF image.
I then re-processed the 3 source pictures using another preset to obtain something more natural for the building and the floor.
Then, I merged both HDR results in a classical pictures editor like Gimp.