Bryan and Cherry Alexander / Zodiac filled with tourists seen through ice arch in an iceberg, Pleneau Island, Antarctica, February 2009.

Bryan and Cherry Alexander / Ice arch iceberg showing the portion underwater that is sculpted by the sea. Polar regions. Digitally created image composite

Bryan and Cherry Alexander / Inuit hunter untangling team of Huskies (Canis familiaris) in front of iceberg. Savissivik, Northwest Greenland, 1997.

Thomas Lazar / Ice hanging from arch in sea cave carved in soft sandstone cliffs, frozen lake, Squaw Bay, Lake Superior, Apostle Islands National Lakeshore, Wisconsin, USA, February 2009

Steven Kazlowski / Arched iceberg floating off the western Antarctic peninsula, Southern Ocean

Hanne & Jens Eriksen / Iceberg, Disko Bay, Greenland summer

Pete Oxford / Emperor Penguins colony (Aptenodytes forsteri) Antarctic

John Shaw / Iceberg with arch in Hall Bredning, Scoresby Sund, Greenland, August.

Ashley Cooper / Gentoo penguins (Pygoscelis papua) with members of an expedition cruise ship. Curverville Island, Antarctic Peninsula.

Ashley Cooper / Arched Iceberg collapsing into the sea, calved from the Jacobshavn glacier or Sermeq Kujalleq, Greenland, July 2008.

Ashley Cooper / Arched Iceberg collapsing into the sea, calved from the Jacobshavn glacier or Sermeq Kujalleq, Greenland, July 2008.

Michel Roggo / Ice archway in iceberg in the sea outside the Ilulissat Icefjord UNESCO World Heritage Site, Greenland, August 2014. Photographed for the Freshwater Project.

Theo Allofs / Large arched iceberg, Svalbard, Norway

Colin Monteath/ Hedgehog House / Iceberg with thin arch at sunset, Cierva Cove, Antarctic Peninsula, Antarctica

Colin Monteath/ Hedgehog House / Iceberg with tunnel at sunset, Cierva Cove, Antarctic Peninsula, Antarctica

Colin Monteath/ Hedgehog House / Kayakers approaching arches in iceberg, Cierva Cove, Antarctic Peninsula, Antarctica

Olga Kamenskaya / View through rock arch of vehicles parked on ice on the surface of Lake Baikal, Siberia, Russia, March 2012.

Thomas Lazar / Icicles hanging from sandstone archway in sea cave at dawn. Apostle Islands National Lakeshore, Lake Superior, Squaw Bay, Wisconsin, February 2014. Exposure composite of 3 images.

Thomas Lazar / Icicles hanging from sandstone archway, Apostle Islands National Lakeshore, Lake Superior, Squaw Bay, Wisconsin, January 2014.

Bryan and Cherry Alexander / Icebergs floating by the heavily glaciated south coast of Scoresbysund Fiord, East Greenland.

Bryan and Cherry Alexander / Iceberg with an ice arch grounded in Marguerite Bay at sunset, Antarctica.

Bryan and Cherry Alexander / Pointed iceberg seen through a hole in an iceberg near Pleneau Island, Antarctic Peninsula, Antarctica.

XI ZHINONG / Matural archway and icy landscape, Antarctica, November 2012.

Jeff Vanuga / Arch of ice floating in Antarctica, November 2011.

Hiroya Minakuchi / Natural arch in iceberg, Greenland

Bryan and Cherry Alexander / Ice arch in iceberg, Cierva Cove, Antarctica, 2009.

Bryan and Cherry Alexander / Iceberg with ice arch grounded in Marguerite Bay, Antarctica, February 2009.

Hiroya Minakuchi / Iceberg with arch and ice floes, Antarctica

Bryan and Cherry Alexander / Ice arch in Marguerite Bay at sunset, south of the Antarctic Circle, Antarctica, February 2009.

Bryan and Cherry Alexander / Iceberg surrounded by melting sea ice in summer, Northwest Greenland, 1997.

Bryan and Cherry Alexander / Inuit hunter untangling team of Huskies (Canis familiaris) by ice arch. Melville Bay, Northwest Greenland, 1998.

Bryan and Cherry Alexander / Inuit hunter untangling team of Huskies (Canis familiaris) in front of iceberg. Savissivik, Northwest Greenland, 1997.

Kevin Schafer / Iceberg broken off from Austfonna Glacier, Nordaustlandet, Svalbard, Norway

Thomas Lazar / Ice hanging from arch in sea cave carved in soft sandstone cliffs, framing sea stack and frozen lake, Squaw Bay, Lake Superior, Apostle Islands National Lakeshore, Wisconsin, USA, February 2009

Konrad Wothe / Iceberg, Antarctic Peninsula, Antarctica

Flip Nicklin / Iceberg with a natural arch, Antarctic Peninsula, Antarctica

Flip Nicklin / Tourists checking out iceberg from inflatable boat from the Endeavour cruise ship, Antarctica

Yva Momatiuk & John Eastcott / Iceberg with large arch sculpted by waves and melting action floats in sea, South Georgia Island

Steven Kazlowski / Polar bear (Ursus maritimus) pair of spring cubs playing on the pack ice in early autumn, off Barter Island and the Arctic National Wildlife Refuge, Alaska

Yva Momatiuk & John Eastcott / Massive blue and white iceberg with arch sculpted by waves and melting action, South Georgia Island

Yva Momatiuk & John Eastcott / Iceberg with large arch sculpted by waves and melting action floats in sea, South Georgia Island

Steven Kazlowski / Arched iceberg floating off the western Antarctic peninsula, Southern Ocean

Yva Momatiuk & John Eastcott / Iceberg with arches and turrets sculpted by waves and melting of ice, Gerlache Passage, Antarctica

Yva Momatiuk & John Eastcott / Iceberg with arches and columns sculpted by waves and melting of ice, Gerlache Passage, Antarctica

Yva Momatiuk & John Eastcott / Iceberg with arches and turrets sculpted by waves and melting of ice, Gerlache Passage, Antarctica

Yva Momatiuk & John Eastcott / Giant iceberg arch formed by ice melting and wave action, Antarctica

Yva Momatiuk & John Eastcott / Giant iceberg arch formed by ice melting and wave action, Antarctica

Suzi Eszterhas / Icebergs at Sunset, Wedell Sea, Antarctica

Flip de Nooyer / Sailboat seen through sea arch in iceberg, Gerlache Strait, Antarctica

Colin Monteath / Iceberg with arch, Petermann Island, Antarctic Peninsula, Antarctica

Konrad Wothe / Ice and peaks, Hintertuxer Glacier, Zillertal, Alps, Tyrol, Austria

Benjamin Olson / Iceberg with hole from melting, Antarctica

Matthias Breiter / Iceberg, Gonzalez Videla Antarctic Base, Paradise Bay, Antarctic Peninsula, Antarctica

Matthias Breiter / Natural arch in iceberg, Gerlache Strait, Antarctic Peninsula, Antarctica

Hiroya Minakuchi / Ice arch in glacial fjord, Greenland, Denmark

Onne van der Wal / Man exploring a natural arch in weathered icebergs off a glacier in Alaska. 2001

Onne van der Wal / The crew of yacht "Shaman" in the yacht's tender, heading through a natural arch in an iceberg, south coast of South Georgia.

Onne van der Wal / The crew of yacht "Shaman" in the yacht's tender, heading towards a natural arch in an iceberg, south coast of South Georgia. Model and Property Released.

Onne van der Wal / A yacht's tender taking a close-up look at a natural arch in an iceberg, south coast of South Georgia.

Onne van der Wal / The crew of yacht "Shaman" in the yacht's tender, heading towards a natural arch in an iceberg, south coast of South Georgia. Model and Property Released.

Onne van der Wal / The crew of yacht "Shaman" in the yacht's tender, heading towards a natural arch in an iceberg, south coast of South Georgia.

Onne van der Wal / A large archway in a naturally carved iceberg, Antarctic Peninsula.

Kevin Schafer / Iceberg broken off from Austfonna Glacier, Nordaustlandet, Svalbard, Norway

Ingo Arndt / Iceberg near Drygalski Fjord, South Georgia Island

Stephen Belcher / Icebergs, Antarctic Peninsula, Antarctica

Roberto Rinaldi / Carved iceberg with natural arch, Antarctic Peninsula.

Colin Monteath / Tourists cruise in inflatable boats, close to large iceberg arch, Enterprise Island, Antarctica Peninsula, Antarctica

Flip de Nooyer / Sailboat seen through sea arch in iceberg, Gerlache Strait, Antarctica

Flip de Nooyer / Sailboat seen through sea arch in iceberg, Gerlache Strait, Antarctica

Flip de Nooyer / Sailboat seen through sea arch in iceberg, Gerlache Strait, Antarctica

Flip de Nooyer / Sailboat seen through sea arch in iceberg, Gerlache Strait, Antarctica

Flip de Nooyer / Sailboat seen through sea arch in iceberg, Gerlache Strait, Antarctica

Colin Monteath / Iceberg with arch, Petermann Island, Antarctic Peninsula, Antarctica

Jeff Foott / Iceberg, Antarctica

Ashley Cooper / Tourists from expedition cruise ship in zodiac between ice arch and rock cliff on Spert Island. Palmer Archipelago, Antarctica. December 2019.

Jeff Vanuga / Iceberg Arch and sunstar along the Antarctic Sound, Antarctica.