If it weren't for the sight of the occasional modern housing development, the 10.5-mile Newport Back Bay loop would be almost like unspoiled backcountry. Curving around Upper Newport Bay, where flora and fauna spring up around the bay's salt-and-freshwater mix, the trail is quiet enough, serene enough and green enough to qualify as one of the best natural outing sites for bikers and hikers alike. You can pedal in via multiple entries off Highway 73 or Pacific Coast Highway and make your way around the bay, stopping, if you'd like, at the Environmental Nature Center, Science Center, Nature Preserve and other such spots along the way. Along with the 35,000 other birds that stop by yearly, several rare or endangered species also nest in the area.