Ventures into abandoned structures are perhaps the most common example of urban exploration. At times, sites are entered first by locals, and may sport large amounts of graffiti and other acts of vandalism. Explorers face various risks in abandoned structures including collapsing roofs and floors, broken glass, guard dogs, the presence of chemicals and other harmful substances, most notably asbestos, hostile squatters and motion detectors. Some explorers wear respirators to protect their airways and proper attire to protect their bodies.
Although targets of exploration vary from one country to another, high-profile abandonments include amusement parks, grain elevators, factories, power plants, missile silos, fallout shelters, hospitals, asylums, schools, poor houses, and sanatoriums.
Many explorers find decay of uninhabited space to be profoundly beautiful and some are also proficient freelance photographers. Abandoned locations can be, at times, heavily guarded with motion sensors and active security. Others are more easily accessible and carry less risk of discovery. An important goal, overall, of exploring a location is to gain access, perform your task, and remove yourself undetected, unscathed, causing no harm to others or that which surrounds you. Abandoned sites are also popular among historians, preservationists, architects, archaeologists, industrial archaeologists, and ghost hunters.