The city of Rome has lots of squares with fountains in them. Pope Alexander wanted to make the city more beautiful, so during his time, more fountains were made. One of the biggest squares in Rome was the Piazza Navona. On one side of the piazza was the church of St. Agnes, built by Borromini. Bernini thought it was an ugly building. He was asked to make the ""Fountain of the Rivers"" in the square, right outside the church. It has four figures who are symbols of four rivers. Bernini carved one of river-figures looking up at the church and throwing his hands in the air in shock at its ugliness. Borromini was very upset with Bernini's joke, which has been there now for more than 300 years.