 Agave on McKittrick Canyon Trail. Guadalupe Mountains National Park, Texas, December 28, 2007
 Hunter Line Cabin in McKittrick Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Bark of alligator juniper in McKittrick Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Slopes of Frijole Mountain from McKittrick Canyon Trail. Guadalupe Mountains National Park, Texas, December 28, 2007
 Echinocereus cacti growing on ruins of Hunter Line shack in McKittrick Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Texas madrone in McKittrick Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Frozen McKittrick Creek. Guadalupe Mountains National Park, Texas, December 28, 2007
 Devil s Hall in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Rocks in Devil s Hall in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Big rocks near Devil s Hall in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Rocks on Devils Hall Trail in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Dead juniper on Devils Hall Trail in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Hiker s staircase in Pine Spring Canyon, on Devils Hall Trail. Guadalupe Mountains National Park, Texas, December 28, 2007
 Upper section of Hiker s Staircase near Devil s Hall in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Guadalupe spring from El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 El Capitan Mountain from a trail near Guadalupe Spring in Guadalupe Mountains National Park. Texas, December 27, 2007
 El Capitan Mountain Trail near Guadalupe Spring in Guadalupe Mountains National Park. Texas, December 27, 2007
 Rocks and El Capitan Mountain from a trail near Guadalupe Spring in Guadalupe Mountains National Park. Texas, December 27, 2007
 Split rock and El Capitan Mountain from a trail near Guadalupe Spring in Guadalupe Mountains National Park. Texas, December 27, 2007
 Peeling bark of Texas madrone on Devils Hall Trail in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Texas madrone (Arbutus xalapensis) on Devils Hall Trail in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 Smooth white bark of Texas madrone on Devils Hall Trail in Pine Spring Canyon. Guadalupe Mountains National Park, Texas, December 28, 2007
 El Capitan Mountain and Trail in Guadalupe Mountains National Park. Texas, December 27, 2007
 El Capitan Mountain from a trail in Guadalupe Mountains National Park. Texas, December 27, 2007
 El Capitan Trail and Mountain in Guadalupe Mountains National Park. Texas, December 27, 2007
 Dead tree from El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 View from beginning of El Capitan Trail in Guadalupe Mountains National Park. Texas, December 27, 2007
 Cactus on rocks of El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 Agaves and El Capitan Mountain from a trail in Guadalupe Mountains National Park. Texas, December 27, 2007
 Hedgehog cactus near El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 Prickly pears near El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 El Capitan Mountain (zoomed), view to the west in Guadalupe Mountains National Park. Texas, December 27, 2007
 Agave, cacti and El Capitan Mountain from a trail in Guadalupe Mountains National Park. Texas, December 27, 2007
 Cushion cactus and El Capitan Mountain from a trail in Guadalupe Mountains National Park. Texas, December 27, 2007
 Prickly pears and yucca near El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 Alligator juniper (Juniperus deppeana) near El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 Magenta tinged echinocereus hedgehog actus on El Capitan Trail. Guadalupe Mountains National Park, Texas, December 27, 2007
 El Capitan Mountain after sunset, view from lower Roadside Park. Guadalupe Mountains National Park, Texas, December 28, 2007
 El Capitan Mountain at sunset, view from lower Roadside Park. Guadalupe Mountains National Park, Texas, December 28, 2007
 El Capitan Mountain, view from lower Roadside Park at morning. Guadalupe Mountains National Park, Texas, December 28, 2007
 El Capitan Mountain, view from upper Roadside Park at morning. Guadalupe Mountains National Park, Texas, December 28, 2007
 El Capitan Mountain with cholla cactus in foreground, view from upper Roadside Park. Guadalupe Mountains National Park, Texas, December 28, 2007
 El Capitan Mountain with prickly pears cactus in foreground, view from upper Roadside Park. Guadalupe Mountains National Park, Texas, December 28, 2007
 El Capitan Mountain from a trail at the foot of the mountain. Guadalupe Mountains National Park, Texas, December 27, 2007
 El Capitan Mountain from southern foot of the mountain. Guadalupe Mountains National Park, Texas, December 27, 2007
 El Capitan Mountain at sunset, view from lower Roadside Park south from the mountain. Guadalupe Mountains National Park, Texas, December 28, 2007
 Icicles on maple leafs in Lemon Tree Park after ice storm. College Station, Texas, January 17, 2007
 A grotto in Delaware and Raritan Canal State Park between Kingston and Princeton. New Jersey, March 28, 2007
 Icicles near Iron Bridge Trail in Lick Creek Park after ice storm. College Station, Texas, January 17, 2007
 A grotto in Delaware and Raritan Canal State Park west from Mapleton Road. Kingston, New Jersey, April 20, 2007
 Santa Elena Canyon and mountains in Mexico from SW3 (Southwest Rim) campsite at sunrise. Big Bend National Park, November 29, 2009
 Canyon of Smokey Creek. Big Bend National Park, Texas, November 25, 2007
 Lower part of Juniper Canyon Trail. Big Bend National Park, Texas, November 23, 2007
 Indian Lodge in Davis Mountains State Park. Fort Davis, Texas, December 29, 2007
 Lower (flat) part of Juniper Canyon Trail. Big Bend National Park, Texas, November 23, 2007
 Boot Rock, view from Juniper Canyon Trail. Big Bend National Park, Texas, November 23, 2007
 Cliff above Indian Lodge in Davis Mountains State Park. Fort Davis, Texas, December 29, 2007
 A view from Newfound Gap Road. Smoky Mountains National Park, Tennessee, May 18, 2007
 A view from Clingmans Dome. Smoky Mountains National Park, Tennessee, May 18, 2007
 Yucca on a hill west from entrance in Davis Mountains State Park. Fort Davis, Texas, December 29, 2007
 On a hill south from Indian Lodge in Davis Mountains State Park. Fort Davis, Texas, December 29, 2007
 Icicles on a shore of Cayuga Lake in Stewart Park. Ithaca, New York, December 4, 2005
 Echo Canyon, view to north-west from Enchanted Rock dome. Fredericksburg, Texas, December 24, 2007
 Northeast Rim, view from lower part of Juniper Canyon Trail. Big Bend National Park, Texas, November 23, 2007
 Rocks near parking at Clingmans Dome. Smoky Mountains National Park, Tennessee, May 18, 2007
 Oconaluftee River near Newfound Gap Road. Smoky Mountains National Park, Tennessee, May 18, 2007
 Purple spineless prickly pears cactus in Davis Mountains State Park. Fort Davis, Texas, December 29, 2007
 Icicles on a tree branch over Cayuga Lake in Stewart Park. Ithaca, New York, December 4, 2005
 Hedgehog cactus (Echinocereus viridiflorus) on northern hill in Davis Mountains State Park. Fort Davis, Texas, December 29, 2007
 Crown Mountain, view from lower part of Juniper Canyon Trail. Big Bend National Park, Texas, November 23, 2007
 Chisos Mountains with snow, view from Castalon Highway. Big Bend National Park, Texas, November 25, 2007
 Magenta tinged prickly pears cactus on northern hill in Davis Mountains State Park. Fort Davis, Texas, December 29, 2007
 Santa Elena Canyon west from Smokey Creek Trail east from Mule Ear Spring. Big Bend National Park, Texas, November 25, 2007
 Columnar jointed palisade appearance of vertical lava flows along Limpia Canyon, view from Road 17. Fort Davis, Texas, December 29, 2007
 Grotto Pavilion and Chesma Pillar on Big Pond in Catherine Park. Pushkin (former Tsarskoe Selo) near Saint Petersburg, Russia, December 3, 2016
 Camping on a small ridge near Juniper Canyon Trail south from Upper Juniper Spring. Big Bend National Park, Texas, November 22, 2007
 Chisos Mountains with traces of snow, view from Castalon Highway (Ross Maxwell Scenic Drive). Big Bend National Park, Texas, November 25, 2007
 Prickly pears cactus on a small ridge near Juniper Canyon Trail south from Upper Juniper Spring. Big Bend National Park, Texas, November 22, 2007
 Stone grotto near Mariyinskaya Alley in Pavlovsk Park. Pavlovsk, suburb of Saint Petersburg, Russia, December 31, 2015
 Echinocactus horizonthalonius (devil s head cactus, or horse crippler) with daggerlike spines on a small ridge near Juniper Canyon Trail south from Upper Juniper Spring. Big Bend National Park, Texas, November 22, 2007
 Mountains on northern side of Nahal Tseelim Canyon, 2 miles north from Masada. The Middle East, January 20, 2001
 Mountains on northern side of Nahal Tseelim Canyon, 2 miles north from Masada. The Middle East, January 20, 2001
 Mountains on northern side of Nahal Tseelim Canyon, 2 miles north from Masada. The Middle East, January 20, 2001
 A stream of Whiteoak Canyon near Skyline Drive. Skyland, Virginia, May 16, 2007
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 - trip to Wichita Mountains with OU Timberline Explorers club Nov. 22, 23 (Norman, Wichita Mountains, November 15 - December 1, 1996)
 A creek near Whiteoak Canyon Trail near Skyline Drive. Skyland, Virginia, May 16, 2007
 Granite grotto in Monrepos Park in Vyborg. Russia, May 24, 2019
 Macey Lake in Sangre de Cristo Mountains. Colorado, July 2, 2007
 Macey Falls in Sangre de Cristo Mountains. Colorado, July 2, 2007
 Southern Macey Lake in Sangre de Cristo Mountains. Colorado, July 2, 2007
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