Arizona

Hoover Dam, a concrete arch-gravity dam in the Black Canyon of the Colorado River on the border between the US states of Arizona and Nevada. Hoover Dam ,finished in 1936, impounds Lake Mead, the largest reservoir in the United States by volume. The dam's generators provide power for public and private utilities in Nevada, Arizona, and California. Hoover Dam is a major tourist attraction; nearly a million people tour the dam each year.

Joe Klamar/AFP

The sun rises over the Hoover Dam, a concrete arch-gravity dam in the Black Canyon of the Colorado River on the border between the US states of Arizona and Nevada. The Hoover Dam was finished in 1936 and impounds Lake Mead, the largest reservoir in theUS by volume.

Firefighter Jesus Acosta holds a candle during a vigil and memorial gathering at the Prescott High School in Prescott, Arizona on July 2, 2013. Acosta is a volunteer firefighter with the Ash Fork fire department, which is located in Yavapai County, Arizona. The Yarnell Hill fire, which killed all but one member of a 20-strong 'hotshot' team, was the biggest loss of firefighters' lives since the September 11 attacks, and the most from a US wildfire in 80 years.

Krista Kennell/AFP

Firefighter Jesus Acosta holds a candle during a vigil and memorial gathering in Prescott, Arizona, US, for 19 colleagues who died in the Yarnell Hill fire, a wildfire caused by record heat and erratic winds. The victims were members of an elite “hotshot” unit and was the biggest loss of firefighters’ lives since the September 11 attacks and the most from a US wildfire in 80 years

A wildfire burns homes in the Glenn Ilah area near Yarnell, Ariz. on Sunday, June 30, 2013. An Arizona fire chief says the wildfire that killed 19 members of his crew near the town was moving fast and fueled by hot, dry conditions. The fire started with a lightning strike on Friday and spread to 2,000 acres on Sunday amid triple-digit temperatures. (AP Photo/The Arizona Republic, David Kadlubowski)

David Kadlubowski/AP

A wildfire burns homes in the Glenn Ilah area near Yarnell, Arizona in the US. An Arizona fire chief says the wildfire, which killed 19 members of his crew near the town, was moving fast, fueled by hot, dry conditions. Read more