 Hall of the Mountain King(?) in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 Stalactites in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 A hall in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 Stalagmites in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 The Watchtower in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 A cave in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 Spacious hall in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 Pluto s Anteroom(?) in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 Stalagmites in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 River Walk underneath a bridge. San Antonio, Texas, October 6, 2007
 "Natural entrance" to Carlsbad Caverns. New Mexico, December 26, 2007
 Serpentine path of "Natural entrance" to Carlsbad Caverns. New Mexico, December 26, 2007
 Mission San Juan. San Antonio, Texas, October 6, 2007
 Riverwalk passage under a bridge. San Antonio, Texas, October 24, 2008
 Mall near River Walk. San Antonio, Texas, October 6, 2007
 Statue near Mission San Juan. San Antonio, Texas, October 6, 2007
 Church of Mission Espada. San Antonio, Texas, October 6, 2007
 A church of Mission San Juan. San Antonio, Texas, October 6, 2007
 Riverwalk at evening, view from a foot bridge. San Antonio, Texas, October 24, 2008
 A stone bridge (1937) across Heathcote Brook in Cook Natural Area. Kingston, New Jersey, April 28, 2007
 A stone bridge across Heathcote Brook in Cook Natural Area at sunset. Kingston, New Jersey, April 2, 2007
 River Walk under E. Houston(?) Street Bridge. San Antonio, Texas, February 9, 2008
 Passage in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Bench at River Walk under E. Pecan(?) Street Bridge. San Antonio, Texas, February 9, 2008
 Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Climbing Turkey Peak in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 A column and other speleothems in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Limestone formations in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Massive stalagmites in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Flowstone feature in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Pointed formations in caves of Carlsbad Caverns. New Mexico, December 26, 2007
 Limestone tunnel in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Narrow passage in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Stalactites and massive stalagmites in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Lions Tails hanging in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Travertine speleothems along a passage in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Weathered stones on a slope of Freshman Mountain in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Cacti east from Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Rocks east from Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Lichens on rocks near Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Weathering of rocks near Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Fresh snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
 Plants in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
 Ocotillo bush near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
 Massive stalagmites in Hall of Giants of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Columns in a small side alcove in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Prickly pear cactus on Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Irregularly rounded- or scallop-shaped passages in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Irregularly shaped limestone formations along a passage of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Bone-shaped limestone formations along a passage of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Stalactites and stalagmites in a small alcove along the side of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Cholla cactus in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
 Huge stalagmite named "Rock of Ages" in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Agaves and cacti in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
 A narrow stalagmite with a large cluster of stalactites in the Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Prickly pears cactus in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
 Rocks on a slope of Freshman Mountain east from Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Speleothems (including stalactites, stalagmites, a column, and helictites) in an alcove of the Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Drapery and ripple-shaped patterns of travertine flowstone speleothems in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Pedestal rock (differential weathering) near Turkey Pass Trail in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Mushroom rocks (differential weathering of shaded sides of rocks) in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 A waterfall of Cavern Cascade in Watkins Glen State Park. New York, October 9, 2005
 A historical bridge across Millstone River bridge during flooding, near Road 27. Kingston, New Jersey, April 16, 2007
 Weathered surface of Enchanted Rock in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 View to the north from Enchanted Rock in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Crass (product of weathering) on Enchanted Rock in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Standing on a granite dome of Enchanted Rock in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
 Alamo mission. San Antonio, Texas, October 24, 2008
 Riverwalk at evening. San Antonio, Texas, October 24, 2008
 Veterans Memorial Bridge, also known as Gramercy Bridge, over Mississippi River. Fog is the result of cooling of warm and humid air. Wallace, west from New Orleans, Louisiana, January 7, 2007
 Mural in Martin Luther King, Jr. Park, near Waco Bridge. Waco, Texas, November 22, 2009
 Historical mural in Martin Luther King, Jr. Park, near Waco Bridge. Waco, Texas, November 22, 2009
 Foggy sunrise at Martin Luther King, Jr. Park, near Waco Bridge. Waco, Texas, November 22, 2009
 Restaurant in area of Navarro Street at Riverwalk at evening. San Antonio, Texas, October 24, 2008
 A tourist on a trail above Whirlwind Gorge taking a picture of a waterfall of Cavern Cascade in Watkins Glen State Park. New York, October 9, 2005
 A small house on Burnett Street near Martin Luther King Jr. Street. Calvert, Texas, January 28, 2007
 Veterans Memorial Bridge, also known as Gramercy Bridge, over Mississippi River, view from a levee near River Road. Wallace, Louisiana, January 7, 2007
 A boardwalk in Cook Natural Area in fog. Princeton, New Jersey, March 23, 2007
 Hotel Valencia and a high-rise building in area of Navarro Street, view from Riverwalk. San Antonio, Texas, October 24, 2008
 A boardwalk in Cook Natural Area through a marsh in fog. Princeton, New Jersey, March 23, 2007
 A marsh boardwalk in Cook Natural Area. Princeton, New Jersey, March 23, 2007
 A marsh in Cook Natural Area at sunset. Kingston, New Jersey, April 2, 2007
 Turkey Peak in Enchanted Rock State Natural Area. Fredericksburg, Texas, December 24, 2007
 Passage between stones on Freshman Mountain in Enchanted Rock State Natural Area. Fredericksburg, Texas, December 24, 2007
 Waterfall of Can Creek from West Trail in Lost Maples State Natural Area. Vanderpool, Texas, December 30, 2007
 Sabinal River from East Trail in Lost Maples State Natural Area. Vanderpool, Texas, December 30, 2007
 Cacti on a slope of Freshman Mountain in Enchanted Rock State Natural Area. Fredericksburg, Texas, December 24, 2007
 A deer on Linear Park Trail (former railroad) in Cook Natural Area, near Ridge Road. Kingston, New Jersey, May 11, 2007
 King Cemetery near Stone Quarry Road. Ithaca, New York, October 23, 2005
 Heathcote Farm (1857, a former State juvenile detention center, now Withington Estate) in Cook Natural Area. Kingston, New Jersey, May 11, 2007
 Smaller Chinese Bridge and Cross Bridge (Krestovy Most) in Alexander Park. Pushkin (former Tsarskoe Selo), south from Saint Petersburg, Russia, October 3, 2016
 City sewage waterfall in Cascadilla gorge, view from a stone foot bridge below and east from Stewart Avenue bridge. Ithaca, New York, October 10, 2005
 King Alfred s cake fungus Daldinia concentrica in Lick Creek Park. College Station, Texas, October 30, 2018
 King Alfred s cake fungus Daldinia concentrica on a log in Lick Creek Park. College Station, Texas, October 3, 2018
 King ranch bluestem grass (Bothriochloa ischaemum) in Lick Creek Park. College Station, Texas, October 7, 2020
 Blooming king ranch bluestem grass (Bothriochloa ischaemum) in Bee Creek Park. College Station, Texas, October 7, 2020
 Inflorescence of king ranch bluestem grass (Bothriochloa ischaemum)(?) in Bee Creek Park. College Station, Texas, October 7, 2020
 View from Brooklyn Bridge. New York City, February 18, 2007
 Rocks, a pond and a foot bridge of Maple Trail, view from East Trail in Lost Maples State Natural Area. Vanderpool, Texas, November 8, 2008
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