Drapery and ripple-shaped patterns of travertine flowstone speleothems 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
Limestone tunnel in 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
Columns in a small side alcove in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
Irregularly rounded- or scallop-shaped passages in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
Speleothems (including stalactites, stalagmites, a column, and helictites) in an alcove of the Big Room of 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
Huge stalagmite named "Rock of Ages" in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
Massive stalagmites in Hall of Giants of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
Grand staircase and cavernous building from the first floor courtyard of Education City Mosque. Doha, Qatar, June 29, 2016
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
Serpentine path of "Natural entrance" to Carlsbad Caverns. New Mexico, December 26, 2007
Narrow passage in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
A column and other speleothems 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
Pointed formations in caves of Carlsbad Caverns. New Mexico, December 26, 2007
The village of Siloah (Silwan) built over ancient caverns of the Jewish necropolis viewed from the opposite side of Kidron Valley. Jerusalem, the Middle East, July 12, 2001
Stalactites and massive stalagmites in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
A cave in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
Cholla cactus in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
Spacious hall in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
Irregularly shaped limestone formations along a passage of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
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
Stalactites in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
Hall of the Mountain King(?) in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
Stalagmites in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
The King s Throne 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
Pluto s Anteroom(?) in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
Bone-shaped limestone formations along a passage of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
Fresh snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
Cave of Brightness (Musfer Cavern, Dahl Al Misfir sinkhole) from its bottom in Umm Al Shabrum south-west from Doha. Qatar, February 27, 2015
Cavernous structure and staircase of Education City Mosque. Doha, Qatar, June 29, 2016
A waterfall of Cavern Cascade in Watkins Glen State Park. New York, October 9, 2005
Stalagmites in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
Morning beam of light in Cave of Brightness (Musfer Cavern, Dahl Al Misfir sinkhole) in Umm Al Shabrum south-west from Doha. Qatar, February 27, 2015
A hall in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
Karst feature in Cave of Brightness (Musfer Cavern, Dahl Al Misfir sinkhole) in Umm Al Shabrum south-west from Doha. Qatar, February 27, 2015
Texture of Cave of Brightness (Musfer Cavern, Dahl Al Misfir sinkhole) in Umm Al Shabrum south-west from Doha. Qatar, February 27, 2015
Agaves and cacti in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
Limestone formations in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
Grand staircase and cavernous building from the first floor courtyard of Education City Mosque in dusk. Doha, Qatar, June 28, 2016
Angels Showers waterfall in a cave of Ozark Caverns in Lake of the Ozarks State Park. Missouri, September 10, 2005
A cave of Ozark Caverns in Lake of the Ozarks State Park. Missouri, September 10, 2005
Plants in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
Cave of Brightness (Musfer Cavern, Dahl Al Misfir) sinkhole in south central area. Qatar, February 19, 2010
Interior of Cave of Brightness (Musfer Cavern, Dahl Al Misfir) sinkhole in south central area. Qatar, February 19, 2010
Prickly pears cactus 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
Cavernous structure of Education City Mosque. Doha, Qatar, June 29, 2016
Grand staircase and cavernous building from the first floor courtyard of Education City Mosque. Doha, Qatar, June 28, 2016
Light beam in Cave of Brightness (Musfer Cavern, Dahl Al Misfir sinkhole) in Umm Al Shabrum south-west from Doha. Qatar, February 27, 2015
Liverwort Cavernous Crystalwort (Riccia cavernosa) with balloonwort on a muddy shore of Flag Pond on Lake Somerville Trailway near Nails Creek Unit of Somerville Lake State Park. Texas, March 10, 2021
Cavernous Crystalwort (Riccia cavernosa) on a muddy shore of Flag Pond on Lake Somerville Trailway near Nails Creek Unit of Somerville Lake State Park. Texas, March 10, 2021
Close-up of Cavernous Crystalwort (Riccia cavernosa) on a muddy shore of Flag Pond on Lake Somerville Trailway near Nails Creek Unit of Somerville Lake State Park. Texas, March 10, 2021
Cavernous Crystalwort (Riccia cavernosa) under a dry bush of Sesbania on a muddy shore of Flag Pond on Lake Somerville Trailway near Nails Creek Unit of Somerville Lake State Park. Texas, March 10, 2021
Cavernous Crystalwort (Riccia cavernosa) and Texas balloonwort (Sphaerocarpos texanus) on a muddy shore of Flag Pond on Lake Somerville Trailway near Nails Creek Unit of Somerville Lake State Park. Texas, March 10, 2021
Close-up of Cavernous Crystalwort (Riccia cavernosa) taken from a muddy shore of Flag Pond on Lake Somerville Trailway near Nails Creek Unit of Somerville Lake State Park. Texas, March 10, 2021
