John Abbott / Grote's bertholdia moth (Bertholdia trigona) on twig, Big Bend National Park, Texas, USA. August.

Tim Fitzharris / Canyon cliffs, The Window near Walhalla Overlook, North Rim, Grand Canyon National Park, Arizona

Jeff Foott / Yellow Rock Nettle (Eucnide bartonioides) flowering, Big Bend National Park, Texas

Jeff Foott / Yellow Rock Nettle (Eucnide bartonioides) flowering, Big Bend National Park, Texas

Jeff Foott / Yellow Rock Nettle (Eucnide bartonioides) flowering, Big Bend National Park, Texas

Jeff Foott / Cactus and Rio Grande, Big Bend National Park, Texas

Jeff Foott / River at dawn, Rio Grande, Big Bend National Park, Texas

Jeff Foott / Rock patterns, Glenn Springs, Big Bend National Park, Texas

Jeff Foott / Collared Peccary (Tayassu tajacu) skull and patterned rock, Big Bend National Park, Texas

Jeff Foott / Rock patterns, Glenn Springs, Big Bend National Park, Texas

Jeff Foott / Opuntia (Opuntia sp) cactus, Cerro Castellan, Big Bend National Park, Texas

Jeff Foott / Cerro Castellan, ancient volcanic peak, Big Bend National Park, Texas