Grand Canyon

• A small water fall empties into the lake inside the huge Cathedral in the Desert rock formations in Clear Creek Canyon at Lake Powell near Page, Arizona.
  
  
  

  David McNew, Getty Images

• A bleached "bathtub ring," the result of a six-year drought that had dramatically dropped the level of the reservoir, shows in contrast to the red Navajo sandstone formations near Last Chance Bay at Lake Powell near Page, Arizona. More recently, the Secretary of the Interior, Dirk Kempthorne, pulled the levers at Glen Canyon Dam to release high flows into the Colorado River, a part of which runs the 277 mile length of Grand Canyon National Park.
  
  
  

  David McNew, Getty Images

• Boaters stop inside the huge lake-flooded Cathedral in the Desert rock formations in Clear Creek Canyon at Lake Powell near Page, Arizona.
  
  
  

  David McNew, Getty Images

• Prior to the European emigration, the area was inhabited by Native Americans who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon a holy site and made pilgrimages to it.
  
  
  

  David Rogowski, AOL

• The major geologic exposures in Grand Canyon range in age from the 2-billion-year-old Vishnu Schist at the bottom of the Inner Gorge to the 230-million-year-old Kaibab Limestone on the Rim.
  
  
  

  David McNew, Getty Images

• A rainbow appears under dark clouds as a rain storm comes to Lake Powell.
  
  
  

  David McNew, Getty Images

• Weather conditions in the Grand Canyon can greatly affect hiking and canyon exploration. Visitors should obtain accurate forecasts because of hazards posed by exposure to extreme temperatures, winter storms and late summer monsoons.
  
  
  

  Corbis RF

• Lightning strikes as a much-needed rain storm comes to Lake Powell which is marked by a 100-foot thick "bathtub ring" of bleached sandstone.
  
  
  

  David McNew, Getty Images

• Longstanding scientific consensus has been that the canyon was created by the Colorado River over a period of six million years.
  
  
  

  Getty Images

• People take the first official walk on the Skywalk, billed as the first-ever cantilever-shaped glass walkway extending 70 feet from the western Grand Canyon's rim more than 4,000 feet above the Colorado River, on March 20, 2007 on the Hualapai Reservation at Grand Canyon, Arizona.
  
  
  

  David McNew, Getty Images