Agrigento. Capital of the province of the same name, Agrigento holds a rather odd record - its modern population is several times smaller than what it used to be 2,500 years ago. Back in those ancient days, it was known as Akragas and was an important and wealthy Greek colony. This legendary heritage survives to the present day via the Valley of the Temples, an archaeological complex of impressive Doric structures that is a UNESCO World Heritage Site. Otherwise, Agrigento is a lovely town with a laid back atmosphere, interesting medieval architecture, and a number of beautiful nearby beaches. The southern part of Sicily where Agrigento is located is generally a lot less developed and discovered than the north - expect fewer tourists, more authenticity and a lot of genuine cordiality.
Enna. If the south of Sicily is less explored, it is doubly true for the inland parts of the island - including the town and province of Enna (or Castrugiuvanni, as it's known in Sicilian). That doesn't mean there's nothing to see there - in fact, located at the height of 930 m (3,050 ft), the town is the highest provincial capital in Italy and offers truly amazing views of the rest of the island below. In addition to spectacular viewpoints (and winding mountain roads), Enna is also home to quaint villages, the impressive Lombardia Castle, and delicious local cuisine. Some viewing platforms and parts of Old Enna can only be accessed on foot, but you can find a place to park and enjoy this scenic town at a more leisurely pace.
Gorges of Alcantara. Meaning 'the arch' in Arabic, the language from which it got its name, the Alcantara rivers flows for 52 km (32 mi) from Nebrodi Mountains past Mount Etna and towards the eastern coast of Sicily where it empties into the Mediterranean sea. Although the river is not that long, its middle section is home to one of the most impressive natural wonders of the island - the gorges of Alcantara. Made up of eroded black lava, this picturesque and otherworldly place is home to impressive views, long hiking trails and a geological and botanical park. Trout and carp swim in the river, olive and chestnut trees grow in the nearby valleys, and you might even get to spot a kingfisher or a wild cat. Despite being located near the coast, roughly halfway between Catania and Messina, this is a true off-the-beaten-track destination - even some native Sicilians don't know about it.