The fabulous natural formation known as Tonto Bridge was formed over countless centuries of attrition, as Pine Creek scoured through a massive dam of calcium carbonate. Some 183ft high and spanning a 150ft-wide canyon, the resulting travertine bridge is thought to be the world's largest, and is the centerpiece of a thickly wooded state park with splendid walking trails. Snow and high waters may close some trails, or the entire park – check the website for updates.
The park entrance is 3 miles off Hwy 87; the final stretch of the access road is precipitous and winding, and an adventure in itself. Last entry is an hour before closing time.
