St. Anthony preaching to the fishes, who put their heads out of the water to listen. The hard-hearted townsfolk of Rimini who had refused to listen to him were impressed.
The Miracle of the Mule. A mule that hadn't eaten for three days bowed down before the Host instead of heading for the truss of hay.
But he was most famous in his life for his wonderful preaching - he was known as the "Hammer of the Heretics" and the "Living Ark of the Covenant."
I've been to Rimini several times; it takes a lot to impress them. Just south of Rimini is the city of Termoli where a beautiful, albeit contemporary Catholic church, has been built with a fisherman's theme. The interior of the church is decorated with tiles that form patters similar to those in the picture of St. Anthony lecturing to the fish.