It was actually a panoramic with several shots from the 21mm stitched together giving it that look. I did lens correction inside ACR before doing the pano stitch in Photoshop but nothing other than that. I don't usually shoot stitched shots with the 21mm but I may do more of it in the future. It turned out ok I think. Glad you like it aquilan!

Wow. It looks like fisheye projection. Was is perspective corrected anyhow?