If there is a place where there aren't any pigeons, I don't think I've been there. They seem to be everywhere; wherever people congregate, so do they.
One strange thing I've noticed about them is that they can die while standing up, and then remain standing even after they are dead.
On a chilly spring morning not too many years ago, on my way back from a coffee shop, I saw two pigeons at the foot of a big cement planter by the edge of a bridge. One of them was standing right next to the planter, close enough to be completely out of the rain (which was coming down at an angle). Its head was slumped way forward. The other one was sort of standing beside the first, away from the planter. It seemed to be making little noises towards the first one.
Later that morning, after the rain had stopped, I came back to that same place. The first pigeon was still there, and still in that same slumped forward position, but this time it was all alone. I guess its companion must've finally realized that it wasn't going to wake up and left.