Jane Burton / Domestic Cat, ginger kittens with arched back in play posture, fur standing on end and staring at sibling

Tim Fitzharris / Arched rock, Pescadero State Beach, California

Mitsuaki Iwago / Domestic Cat (Felis catus) grey kitten in defensive posture with back arched and hair raised

Jose B. Ruiz / Arched balcony, Zoco, Casco antiguo, Cordoba, Andulcia, Spai

Angelo Giampiccolo / Interior of Monreale Cathedral (officially Santa Maria la Nuova), Sicily, formed from a fusion of artistic styles. ^^^The Normans conquered Sicily from about 1061 to 1091. This cathedral was built at...

Flip de Nooyer / Arched iceberg, Antarctica

Fred Bavendam / Horseshoe Crab (Limulus polyphemus) with American Slipper Limpet (Crepidula fornicata) clinging to its shell, Cape May, New Jersey