Piazza San Francesco, in the centre of Ravenna, hides many treasures. One of them definitely is the basilica that gives the name to the piazza. In the 14th century, the basilica was one of the favourite places of no less than the Supreme Poet Dante Alighieri.
The admission is free, and with just a €1-fee, you can see the amazing submerged crypt. It is a work of art suspended in time, decorated with an ancient mosaic floor completely underwater, and the water level rises and lowers according to rain.
A little advice! Sharp your eyes: you will see a number of goldfish happily swims.