The Loop, a 131-mile multi-use trail that spans the Tucson metro area, officially opens Saturday. The trail allows cyclists, pedestrians, joggers and equestrians to travel along Tucson’s major river banks. It links more than 30 public parks. For the last four days, founder of Trails Inspire, Sirina Dufault and her friend Liz Thomas have been hiking the loop, which is the longest trail system of its type in the country. They will finish their hike at Kino Sports Complex, during the celebration.