Not all art craves attention, some of it hides in the secret places. Some of it is buried treasure, out in the urban wilderness, left scattered in empty rooms of derelict buildings like strange markings left by an unknown tribe. These works are gifts given only to the occasional explorer, found in abandoned factories, warehouses, industrial sites and deconsecrated churches. This is art you have to earn by leaving the designated areas and heading out past the No Entry signs of the urban environment. A diverse range of artists find themselves attracted to these twilight zones and in recent years something of a movement has come to light, huddled around the idea of urban decay and abandonment as the ultimate canvas.