A sinkhole is a depression or hole in the ground formed by some form of collapse of the surface layer. The can happen by several means including when water and/or sewer lines spring a leak and the subsequent flow causes an erosion of the the surrounding soils. The removal of the soils often results in the collapse of the surface area, often a road way in the area of the underground utilities. However, another type of sinkhole (and the subject of this gallery) called a blue hole and/or a cenote, is found in karst topography where the rain water flows through the under ground rock strata characterized by certain lithologic properties of attributes that distinguish the stratum from adjacent areas. The resulting chemical reduction of the lithologic rock forms the sinkholes.

As a general rule, when a sinkhole is found in an ocean (saltwater location), they are referred to as a Blue Hole, and as a Cenotes when found in a fresh water location. However, this differentiation is not globally used. Furthermore, a sinking stream, stream sink or just a sink are more general terms for a site that drains surface water.

Most all sinkholes are caused by karstification, which is a processes of the dissolution of soluble carbonate rocks, either limestone or dolomite by carbonic acid (H₂CO₃). The carbonic acid is formed when rain water (H₂0) passes through the atmosphere and absorbs carbon dioxide (CO₂). Once the rain water reaches the ground, it may absorb additional carbon dioxide from soil respiration, which comes from organisms in the soil. As this weak solution of carbonic acid flows through the cracks in the carbonate rocks, it begins to dissolve these rocks, turning the topography into one called Karst.

The Karst topography may result in a landscape with a variety of features both beneath the surface as well as on top of the surface, with these features being small scale or very large.

Subterranean features include: aquifers, caves, cavern systems, foibe sinkhole, vertical shafts, foibe (inverted funnel-shaped pit), disappearing streams, reappearing springs.

Aboveground features include: kamenitzas (water containing depressions), karst towers, karst valleys, limestone pavement, magotes (steep sided hill) poljes (flat plains), runnel (above ground streams),

Elev. 4,510 feet (34.8864, -111.7825)

Depth: 660 feet, Cave; additional 180 feet

Coconino National Forest

(34.6491446, -111.7522099)

Natural limestone sinkhole

Montezuma Castle National Monument

Elev. 2,332 feet(37.2403666, -99.9818588)

Found within Big Basin Prairie Preserve.

(27, -83.3)

Submerged blue hole, cave survey 2019

Rim: 112 feet below surface, Sea Cave extends: 236 feet

Elev. 35 feet (26.050556, -81.3425)

Big Cypress National Preserve

(29.407625, -82.476469)

Karst window over a subterranean river.

(29.7071245, -82.3943553)

Devil′s Millhopper Geological State Park

Elev: -47 feet (26.801192, -83.08198)

Submerged blue hole

Depth: 427 feet

Elev. 174 feet (29.964722, -81.998056)

circular sinkhole

Depth: 100 feet

(28.54503319344198, -81.37112418050263)

Sinkhole with fountain and one island.

Depth: 24 feet

(27.0748570, -82.2331092)

Depth: 200 feet

Third magnitude spring

Sinkhole in Karst Topography

Used as a mortuary sinkhole, with hundreds of burials

Elev. -5,459 feet (23.3845263, -82.3322549)

underwater sinkhole in the Straits of Florida

Elev. 49 feet (21.8882495, -159.4187008)

Kauai Island

(40.4616277, -85.7926876)

Created by collapse of limestone cave

Located in limestone quarry.

Elev. (37.150278, -86.153631)

Mammoth Cave National Park

Karst topography landscape

Depth: 300 feet

(30.011111, -91.143056)

Collapsed underground salt dome, First flooded 03 August 2012

(36.6675, -93.3397)

Elev. 4,619 feet (34.940447, -104.673239)

Artesian well and cenote.

Depth: 80 feet, Width: 80 feet

US 66, east of Santa Rosa, NM

Elev. 3,500 feet (33.3174684, -104.3314152)

Nine small deep lakes on eastern escarpment of Pecos River

(33.60833, -104.42639)

Sinkhole with hidden cave, Depth: 90 feet

Salt Creek Wilderness Area

626 feet (41.405944, -82.806861)

A fresh water cenote in Castalia, Erie County, Ohio

Depth: 45 feet

Elev, 1501 feet (35.855833, -84.926944)

Enclosed valley notable for Karst formations on SH 68

(30.0620130, -99.3500048)

A Mortuary Cave on the Edwards Plateau in Kerr County

(30.0033015, -98.0907790)

Blue Hole Regional Park

Elev. 89 feet (30.113611, -94.6425)

Salt Dome with sinkholes

(30.0575878, -100.1092375)

Devil′s Sinkhole State Natural Area

Elev. 8,100 feet (41.9126597, -111.5187851)

Natural sinkhole

Wasatch-Cache National Forest

(37.9354624, -79.1509304)

Mount Joy Pond Natural Area Preserve

(38.2757, -78.7768)

Deep Run Ponds Natural Area Preserve

Elev. 1,926 feet (38.95511, -78.736129)

A sinkhole in karst topography

Due to changes underground, lake is dry.

Elev. 2,819 feet (16.808056, -93.474444)

Giant circular Sinkhole in Karst Plateau.

(18.6211188, -88.1664057)

Depth: 1,380 feet

Deepest known blue hole

Located in Chetumal Bay

(20.3249963, -87.3908164)

An Underwater Cave System of Cenotes

(20.2465538, -87.4640619)

An underwater Cave System of Cenotes

(21.599722, -99.098889)

Open air pit cave in Karst topography

Depth: 1,093 feet

(22.993347, -98.165861)

Thermal water-filled sinkhole of Zacatón system

Elev. feet (21.091, -89.5903)

Dzibilchaltn National Park

(20.6609, -88.5505)

Ik Kil Archeological Park near Chichen itza

(20.687708, -88.567694)

A mortuary sinkhole, limestone plain

(17.31590084981808, -87.53467426603939)

Cirular Diameter: 1043 feet, Depth: 407 feet

Karst limestone

43 miles from mainland of Belize in Lighthouse reef