Sandra Bartocha / Dead Grass (Poaceae sp) stems arched over in winter snow, Neuendorf, Mecklenburg-Vorpommern, Germany, December

Mark Taylor / Tabby kitten stretching with arched back

Martin Camm / Carwardine / Illustration of Indo-Pacific bottlenose / Bottle-nosed dolphin (Tursiops aduncus), Delphnidae (Wildlife Art Company).

Jeff Wilson / Boy studying Koran inside Mosque, Lahore, Pakistan, 2006

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

Juan Manuel Borrero / Stream in Guilleries-Savassona Natural Park. Barcelona, Catalonia, Spain.

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

Mark Taylor / Fluffy black kitten, 9 weeks old, stretching with arched back.

Mark Taylor / Black kitten Buxie, 10 weeks old, in defensive witch's cat display with back arched and hair standing up

Mark Taylor / Black kitten Buxie, 10 weeks old, in defensive witch's cat display.

Mark Carwardine / Bowhead whale (Balaena mysticetus) surfacing, showing distinctive triangular head and arched mouthline, Igloolik, Foxe Basin, Nunavut, Arctic Canada

Brent Stephenson / Humpback Whale (Megaptera novaeangliae) about to dive showing arched tail stock. Drake Passage, near the South Shetland Islands, Antarctica, December.