A weather-beaten sign at Grand Canyon’s Horseshoe Mesa warns hikers to stay out of an area with high radiation. The remote section of the canyon is accessible via Grandview Trail, an old, precarious, and minimally maintained mining route that plunges 2,500 feet (762 m) below its starting point at the South Rim. Click the above image to enlarge, click to read my guide “How to Hike Grand Canyon’s Grandview Trail,” or click to view my high-resolution photo collection from Grand Canyon National Park.