 Limestone formations in 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
 Irregularly shaped limestone formations along a passage of Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Passage in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Massive stalagmites in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Narrow passage in Big Room of Carlsbad Caverns. New Mexico, December 26, 2007
 Flowstone feature 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
 Stalactites and massive stalagmites 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
 Columns in a small side alcove 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
 Stalactites and stalagmites in a small alcove along the side of 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
 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
 Drapery and ripple-shaped patterns of travertine flowstone speleothems 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
 "Natural entrance" to Carlsbad Caverns. New Mexico, December 26, 2007
 Pointed formations in caves of Carlsbad Caverns. New Mexico, December 26, 2007
 Serpentine path of "Natural entrance" to Carlsbad Caverns. New Mexico, December 26, 2007
 Ocotillo bush near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 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
 Cholla cactus in snow near a road between White s City and 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
 Prickly pears cactus in snow near a road between White s City and Carlsbad Caverns. New Mexico, December 26, 2007
 George Ashby s Phillips 66 gas station at crossing of Hwy 285 and FM 652. Orla, New Mexico, December 25, 2007
 Jackie and Hall Olds (Hal Old) store, grocery and cafe at crossing of Hwy 285 and FM 652. Orla, New Mexico, December 25, 2007
 A sign near Orla grocery near historical marker No. 3876 at crossing of Hwy 285 and FM 652. Orla, New Mexico, December 25, 2007
 Orla cafe served to feed workers in oil, gas, and sulphur fields, at crossing of Hwy 285 and FM 652. Orla, New Mexico, December 25, 2007
 Stalagmites in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 Stalagmites 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
 Stalactites 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
 The King s Throne 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
 A marker of a tunnel under Route 27 to towpath in Delaware and Raritan Canal State Park. Kingston, New Jersey, April 16, 2007
 Hall of the Mountain King(?) in Northern Cavern in Natural Bridge Caverns. San Antonio, Texas, October 6, 2007
 PATH tunnel (commuter railroad) in the bathtub (basement) wall of World Trade Center, view from West Street. New York City, March 18, 2007
 Underground tunnel connecting Gatchina Palace with Serebrianoe Lake, near Saint Petersburg. Russia, December 23, 2005
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 - Pecos Wilderness in New Mexico 8/30/97 (Dallas - a trip to New Mexico mountains, July 11 - August 30, 1997)
 Christmas light tunnel decoration "Santa s Lane" in Central Park at rain. College Station, Texas, December 29, 2009
 A room in Museum of Fine Arts. Houston, Texas, June 17, 2007
 Billiards room in Yusupov Palace. Saint Petersburg, Russia, September 6, 2007
 Precious Room of Yusupov Palace. Saint Petersburg, Russia, September 6, 2007
 Red room in Grand Palace. Peterhof, a suburb of Saint Petersburg, Russia, August 31, 2007
 A room in Grand Palace. Peterhof, a suburb of Saint Petersburg, Russia, August 31, 2007
 Statue in Precious Room of Yusupov Palace. Saint Petersburg, Russia, September 6, 2007
 Mirror in Precious Room of Yusupov Palace. Saint Petersburg, Russia, September 6, 2007
 Room in Pavlovsky Palace. Pavlovsk, a suburb of Saint Petersburg, Russia, August 29, 2007
 Gold Drawing-room in Hermitage museum. Saint Petersburg, Russia, August 14, 2007
 Entrance of Majolica Room in Hermitage museum. Saint Petersburg, Russia, August 14, 2007
 Living room in Pavlovsky Palace. Pavlovsk, a suburb of Saint Petersburg, Russia, August 29, 2007
 Room corner in Grand Palace. Peterhof, a suburb of Saint Petersburg, Russia, August 31, 2007
 Room with portraits in Grand Palace. Peterhof, a suburb of Saint Petersburg, Russia, August 31, 2007
 Decorated room in Grand Palace. Peterhof, a suburb of Saint Petersburg, Russia, August 31, 2007
 Green room in Grand Palace. Peterhof, a suburb of Saint Petersburg, Russia, August 31, 2007
 Red living room in Pavlovsky Palace. Pavlovsk, a suburb of Saint Petersburg, Russia, August 29, 2007
 Dining room in Grand Palace. Peterhof, a suburb of Saint Petersburg, Russia, August 31, 2007
 Skeletal remains of a pier that used to hold Balinese Room, a nightclub and a former dancing hall and an illegal casino at 2108 Seawall Boulevard that extended 600 feet from Seawall Boulevard at 21st Street into the Gulf of Mexico and that was washed away by hurricane Ike. Galveston, Texas, November 15, 2008
 Entrance of Tukish Room from Mauritanian Parlor in Yusupov Palace. Saint Petersburg, Russia, September 6, 2007
 Room in Alexander Palace. Tsarskoe Selo (Pushkin), suburb of Saint Petersburg, Russia, September 2, 2007
 Reading room in Alexander Palace. Tsarskoe Selo (Pushkin), suburb of Saint Petersburg, Russia, September 2, 2007
 Reconstruction of Soviet style boiler-room (kotelnaya) in Museum of Political History (Kshesinskaya Mansion). Saint Petersburg, Russia, August 25, 2007
 Billiard Room (Turkish Room) of Yusupov Palace. Saint Petersburg, Russia, July 8, 2009
 Fossilized oyster sea shells Ostrea latimarginata(?) in a limestone layer (Dukhan Limestone Member) of Dammam Formation in Jaow Al Hamar depression south from Trainah. Southern Qatar, November 6, 2015
 Limestone cliffs rocks of rocky ridge of Jebel Fuwairit. Northern Qatar, December 12, 2014
 Southern limestone hill on Purple Island (Jazirat Bin Ghanim). Al Khor, Qatar, December 20, 2015
 Railroad tunnel of Katy Trail in Rocheport. Missouri, September 7, 2005
 Web tunnel in Antique Rose Emporium. Independence, Texas, September 28, 2018
 Limestone quarry at sunrise at Jabal Al Jassasiya site, on north-eastern coast. Qatar, December 12, 2015
 Sunrise over a limestone quarry at Jabal Al Jassasiya site, on north-eastern coast. Qatar, December 12, 2015
 A room in Grand Palace in Peterhof. Near Saint Petersburg, Russia, December 22, 2005
 A living room in Gatchina Palace near Saint Petersburg. Russia, December 23, 2005
 QNHG (Qatar Natural History Group) exploring fossils in limestone layer (Dukhan Limestone Member) of Dammam Formation in Jaow Al Hamar depression south from Trainah. Southern Qatar, November 6, 2015
 Shells and limestone peaces on north side of Purple Island (Jazirat Bin Ghanim). Al Khor, Qatar, December 20, 2015
 Grand Palace in Peterhof, a dining room. Near Saint Petersburg, Russia, December 22, 2005
 A living room in Grand Palace in Peterhof. Near Saint Petersburg, Russia, December 22, 2005
 A dining room in Grand Palace in Peterhof. Near Saint Petersburg, Russia, December 22, 2005
 A room in Pavlovsky Palace. Pavlovsk, suburb of Saint Petersburg, Russia, December 24, 2005
 Area of West Bay from Room 1604 of Dareen Tower. Doha, Qatar, December 1, 2013
 Lights of West Bay from Room 1604 of Dareen Tower. Doha, Qatar, December 1, 2013
 Pedestrian tunnel of 1400 Smith Street Building. Houston, Texas, January 21, 2008
 View of Rosh Hanikra, with a railway tunnel (now closed). The Middle East, September 7, 2000
 Arbor tunnel in Letny Sad (Summer Garden). Saint Petersburg, Russia, September 4, 2016
 Green tunnel in Letny Sad (Summer Garden). Saint Petersburg, Russia, September 4, 2016
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