There r plenty of churches in Italy and plenty of outstanding mosaics in Ravenna. So, why St. Francis? Allright, it's the earliest example in Italy of the decorative use of majolica. It is also very beautiful outside - u can see on other photos here . Plus it stuck between tomb of Dante Alighieri and to Cripta Rasponi (Palazzo dela Provinsia) - both are famose themselves. The significance of this church is that remaining mosaic floor of crypt (9-10C) is under water.