Urban exploration (often shortened as UE, urbex and sometimes known as roof and tunnel hacking) is the exploration of manmade structures, usually abandoned ruins or hidden components of the manmade environment. Photography and historical interest/documentation are heavily featured in the hobby, sometimes involving trespassing onto private property. Urban exploration is also called draining (a specific form of urban exploration where storm drains or sewers are explored), urban spelunking, urban rock climbing, urban caving, building hacking, or mousing. The activity presents various risks, including physical danger and, if done illegally and/or without permission, the possibility of arrest and punishment. Some activities associated with urban exploration violate local or regional laws and certain broadly interpreted anti-terrorism laws, or can be considered trespassing or invasion of privacy. Exploration sites Abandonments Ventures into abandoned structures are perhaps the most common example of urban exploration. Many sites are entered first by locals and may have graffiti or other kinds of vandalism, while others are better preserved. 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, prisons, schools, poor houses, and sanatoriums. In Japan, abandoned infrastructure is known as (literally "ruins"), and the term is synonymous with the practice of urban exploration. are particularly common in Japan because of its rapid industrialization (e.g., Hashima Island), damage during World War II, the 1980s real estate bubble, and the 2011 Tōhoku earthquake and tsunami. Many explorers find the decay of uninhabited space profoundly beautiful, and some are also proficient freelance photographers who document what they see, such as those who document the infrastructure of the former USSR. Abandoned sites are also popular among historians, preservationists, architects, archaeologists, industrial archaeologists, and ghost hunters. Active buildings Another aspect of urban exploration is the practice of exploring active or in use buildings, which includes gaining access to secured or "member-only" areas, mechanical rooms, roofs, elevator rooms, abandoned floors, and other normally unseen parts of working buildings. The term "infiltration" is often associated with exploring active structures. People entering restricted areas may be committing trespass, and civil prosecution may result. Catacombs Catacombs such as those found in Paris, Rome, Odessa, and Naples have been investigated by urban explorers. Some consider the Mines of Paris, comprising many of the tunnels that are not open to public tours, including the catacombs, the "Holy Grail" due to their