Katie: In my world everyone is a pony, and they all eat rainbows, and poop butterflies.
When Horton first crosses the bridge he breaks all of the planks. Then at the end when the angry mob goes to get him, they seem to have crossed the fully broken bridge to get to the other side.
In the scene where the Who's finally discover that Horton is real, the Mayor begins introducing random townspeople to Horton. When he introduces Bert, watch closely: Bert is drinking from a mug that has the Blue Sky Productions logo on it, one of the companies that produced Horton Hears a Who.