Gavin Hellier / People commuting through glass walled passageway in modern building, Berlin, Germany, 2009. No release available.

Doc White / Girl in aquarium watching Beluga / White Whale (Delphinapterus leucas) in aquarium. Captive. Model released.

Stephen Dalton / Gecko (Tarentola sp) close up of feet gripping glass, controlled conditions

Pal Hermansen / Old rusting car with plants growing inside, Bastnas car graveyard, Varmland, Sweden, June.

John Cancalosi / Obsidian, a volcanic glass rock, from Idaho, USA.