Fisheye geometry

What I like in this photo is the way how lines are appearing when using fisheye lens. These are Samyang fisheye (purely manual) lens, and I like how vertical lines are distorted and horizontal ones going deep into the photo (from the perspective of viewer standing there). This was done under the bridge in Vilnius. Actually it was rather difficult to get symetry (of pillars framing the picture) as due to the really wide angle of view (180 degrees) even a small move resulted in lost symetry. Even now it is not that perfect.