Shooting the rapids in a raft on the Colorado River, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Shooting the rapids in a raft on the Colorado River, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Skip Brown surfs his whitewater kayak on a glassy standing wave on the Colorado River through the Grand Canyon, Arizona, United States of America, North America

Skip Brown paddles his whitewater kayak through rapids on the Colorado River through the Grand Canyon, Arizona, United States of America, North America

Rapids on the Colorado River, Marble Canyon, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Skip Brown surfs his whitewater kayak on a glassy standing wave on the Colorado River through the Grand Canyon, Arizona, United States of America, North America

Shooting the rapids in a raft on the Colorado River, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Shooting rapids in a kayak on the Colorado River, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Commercial dory runs the Deubendorff Rapid, just past river mile 132, Grand Canyon National Park, Arizona, United States of America, North America

Commercial rafters run the Lava Falls Rapid, just before river mile 180, Grand Canyon National Park, Arizona, United States of America, North America

Commercial dory runs the Deubendorff Rapid, just past river mile 132, Grand Canyon National Park, Arizona, United States of America, North America

Commercial rafters run the Sheer Wall Rapid, just past river mile 14, Grand Canyon National Park, Arizona, United States of America, North America

Shooting the rapids in a raft on the Colorado River, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Shooting rapids in a kayak on the Colorado River, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Commercial rafters run the Lava Falls Rapid, just before river mile 180, Grand Canyon National Park, Arizona, United States of America, North America

Commercial rafters run the Deubendorff Rapid, just past river mile 132, Grand Canyon National Park, Arizona, United States of America, North America

Shooting rapids in a kayak on the Colorado River, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Commercial oar boat runs the Deubendorff Rapid, just past river mile 132, Grand Canyon National Park, Arizona, United States of America, North America

Road near brown agriculture crop field

Workers building a natural gas pipeline, Grand Rapids, Michigan, USA

Hikers swim in the pool below 180-foot Deer Creek Falls in the Grand Canyon outside of Fredonia, Arizona November 2011. The 21.4-mile loop starts at the Bill Hall trailhead on the North Rim and descends 2000-feet in 2.5-miles through Coconino Sandstone to the level Esplanada then descends further into the lower canyon through a break in the 400-foot-tall Redwall to access Surprise Valley. Hikers connect Thunder River and Tapeats Creek to a route along the Colorado River and climb out Deer Creek.

Two women on an inflatable raft going through a rapid, Grand Canyon, Arizona.

Rowing the rapids of the Colorado River's Grand Canyon in a 16 foot raft

A wooden dory running Lava Falls Rapid, Grand Canyon National Park, Arizona.

Hikers past small waterfalls along Deer Creek Narrows in the Grand Canyon outside of Fredonia, Arizona November 2011. The 21.4-mile loop starts at the Bill Hall trailhead on the North Rim and descends 2000-feet in 2.5-miles through Coconino Sandstone to the level Esplanada then descends further into the lower canyon through a break in the 400-foot-tall Redwall to access Surprise Valley. Hikers connect Thunder River and Tapeats Creek to a route along the Colorado River and climb out Deer Creek.

Angelina Wolf kayaking on the Colorado river, Grand Canyon, Arizona.

A wooden dory is tossed in the whitewater of 24-Mile Rapid on the Colorado River in Grand Canyon National Park, Arizona.

Rafts running the white water of Crystal Rapid, mile 98, Colorado River, Grand Canyon.

Rainbow at top of Waterwheel Falls on the Tuolumne River, Grand Canyon of the Tuolumne, Yosemite National Park