Avio, Italy. Avio is a small town located in the Trentino region of northern Italy, known for its castle and beautiful mountain scenery. Visit Castello di Avio, a medieval fortress perched on a hilltop, offering panoramic views of the Adige Valley. Explore the town center and admire the well-preserved historic buildings. Enjoy hiking and biking in the surrounding mountains and valleys. Avio is a hidden gem for those seeking a peaceful retreat in nature.