John Shaw / Shoreline of Lake Powell, seen from Alstrom Point on Romana Mesa. Glen Canyon National Recreation Area, on the Arizona/Utah border, USA, January.

Jack Dykinga / Hoodoo with rock cap on textured Dakota stone and softer Entrada sandstone, sunset, Glen Canyon National Recreation Area, Arizona, USA

Yva Momatiuk & John Eastcott / Sandstone hills along lake, Lake Powell, Glen Canyon National Recreation Area, Utah

Jouan Rius / Balanced Rock, Glen Canyon National Recreation Area, Arizona, USA.

Jouan Rius / Balanced Rock, Glen Canyon National Recreation Area, Arizona, USA, December 2012.

Norbert Wu / Glen Canyon Dam on the Colorado River which generates hydroelectric power and the Glen Canyon Bridge, Glen Canyon National Recreation Area, Arizona

Yva Momatiuk & John Eastcott / Three hundred sixty degree view of Colorado River at Horseshoe Bend, Glen Canyon National Recreation Area near Page, Arizona

Yva Momatiuk & John Eastcott / Dry and cracking cakes of silt deposited by Colorado River during flood and drying during drought, fall morning, Glen Canyon National Recreation Area, Utah

Yva Momatiuk & John Eastcott / Dry and cracking cakes of silt deposited by Colorado River during flood and drying during drought, fall morning, Glen Canyon National Recreation Area, Utah

Yva Momatiuk & John Eastcott / Dry and cracking cakes of silt deposited by Colorado River during flood and drying during drought, fall morning, Glen Canyon National Recreation Area, Utah

Tim Fitzharris / Silted river flowering through Glen Canyon National Recreation Area, Utah

Tim Fitzharris / Lake Powell, Glen Canyon National Recreation Area, Utah