Crystal-encrusted apartment

 2008 09 Rog460
London artist Roger Hiorns covered every square inch of an abandoned apartment with blue copper phosphate crystals. Called "Seizure," it looks like a magical cave from some fantasy novel. From Shape And Colour:
After reinforcing the walls and ceiling and covering them in plastic sheeting, 80,000 litres of a copper sulphate solution was poured in from a hole in the ceiling. After a few weeks the temperature of the solution fell and the crystals began to grow. The remaining liquid was pumped back out and sent for special chemical recycling.
Roger Hiorns's crystal apartment (Thanks, Kirsten Anderson!)