This is a really beautiful Piazza with plenty to see. In this piazza alone you can visit ancient Roman amphitheatre ruins, visit Chiesa di San Biagio, see a statue of Vincenzo Bellini, see Palazzo Tezzano and do some great people watching.
It was here that I used a helpful Italian phrase to get rid of a begger, "Sono al verde", I am broke, and he left us alone after that.
This is one of the biggest and most important piazzas in the city. Named after a poet who lived in and fell in love with Catania, this piazza is packed with interesting things, both above and below. The most interesting things are invisible: the city has been destroyed many times by lava and earthquakes, and when, after one such disaster, the Roman amphiteatre withstood destruction, the inhabitants of the city decided to build OVER it, hoping for a solid foundation. There are the remains of an entire city buried under modern central Catania.
To be found here: Statue of Bellini, Buried Roman Amphiteatre, Candy Vendors
A word on the candy vendors - they sell all sorts of typical Sicilian goodies, particularly during the Christmas holidays and during the festival of St. Agata (which passes through here). I reccommend the candied almonds and 'olives of the Saint'.
To be found nearby: Goods Market, Fruit Market, Via Etnea