城市探險

城市探險，也稱為都市探險、都市探索（英語：Urban exploration，縮寫UrbEx）等，是指對人造結構的探索。探索對象通常是廢棄的建築物，或者是某些未廢棄建築物的不為人知的隱藏部分。在城市探險中，很多人會進行攝影，有時會伴隨着對歷史事件的探索。

城市探險存在各種風險，這也包括法律風險。如果非法進行活動，可能會被懲罰。與城市探索相關的一些活動如違反了當地法律法規，可能會被視為非法侵入或侵犯隱私。

探險地點

廢墟

廢墟可能是最熱門的城市探險地點。很多廢墟最開始由本地人進入，並且可能有塗鴉或其他形式的破壞公物，而另一些則保存得更好。儘管各國各地的可供探索的地點各不相同，但遊樂園、穀物升降機、工廠、發電廠、導彈發射井、防空洞、醫院、收容所、監獄、學校、貧民房和療養院等地區通常會備受矚目。

在日本，廢棄的基礎設施通常被稱為haikyo（意為「廢墟」），和城市探索是同義詞。 haikyo在日本非常常見，這可能由日本過於快速的工業化、二戰時的破壞、80年代的房地產泡沫以及2011年東日本大地震和海嘯造成。

澤爾賈瓦的地下軍用機場

在波斯尼亞和黑塞哥維亞坐落着澤爾賈瓦空軍基地（Željava Air Base），一個大型的地下設施。它與1992年被廢棄。它位於普列塞維察山（Plješevica mountain）下，靠近比哈奇市（Bihać）。它曾是南斯拉夫最大的地下機場，南斯拉夫的空軍基地，歐洲最大的空軍基地之一。它有着總長3.5千米的隧道和一些大型設備。現如今，它已成為熱門的城市探索景點。然而，1990年波斯尼亞戰爭所遺留的地雷仍可能存在於此處。

很多廢墟探索者發現了無人居住建築的破損的美感，有些探索者也是記錄所見所聞的自由攝影師，例如那些記述USSR的基礎設施的人。

仍在使用的建築

法國一個石灰岩採石場內的

另一種城市探險是探索仍在使用的建築，包括「閒人勿進」區域，機械室，建築的屋頂，電梯機房，樓房中長久未被使用的樓層等建築2中不為知的部分。 "infiltration"（意為滲透）一詞通常與探索仍在使用的建築有關。某些場所禁止外人進入，蓄意進入的探險者可能會侵權。

墓穴

Catacombs (France)

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 extensive nature and history. Explorers of these spaces are known as cataphiles.

Sewers and storm drains

Storm drain outfall in Saint Paul, Minnesota

Entry into storm drains, or "draining", is another common form of urban exploration. Groups devoted to the task have arisen, such as the Cave Clan in Australia. Draining has a specialized set of guidelines, the foremost of which is "When it rains, no drains!", because the dangers of becoming entrapped, washed away, or killed increase dramatically during heavy rainfall.

A small subset of explorers enter sanitary sewers. Sometimes they are the only connection to caves or other subterranean features. Sewers are among the most dangerous locations to explore owing to the risk of poisoning by buildups of toxic gas (commonly methane, hydrogen sulfide, or carbon dioxide). Sewers can contain viruses, bacteria, protozoa, and parasitic worms. Protective equipment is recommended for people who enter sewers.

Transit tunnels

Diesel trains in a tunnel of Metro-2 D6 line in Moscow, Russia

Exploring active and abandoned subway and railway tunnels, bores, and stations is often considered trespassing and can result in civil prosecution due to security concerns. As a result, this type of exploration is rarely publicized. An exception to this is the abandoned subway of Rochester, New York, the only American city with an abandoned subway system that was once operational. The Cincinnati subway is also abandoned but was never completed. London has a number of stations on the London Underground network that have been closed over the years, with Aldwych tube station a popular location for explorers.

Utility tunnels

主條目：Utility tunnel

Utility tunnel in the center of Zürich, Switzerland

Universities, and other large institutions, such as hospitals, often distribute hazardous superheated steam for heating or cooling buildings from a central heating plant. These pipes are generally run through utility tunnels, which are often intended to be accessible solely for the purposes of maintenance. Nevertheless, many of these steam tunnels, especially those on college campuses, have a tradition of exploration by students. This practice was once called "vadding" at the Massachusetts Institute of Technology, but students there now call it roof and tunnel hacking.

Some steam tunnels have dirt floors, poor lighting and temperatures above 45 °C（113 °F）. Others have concrete floors, bright light, and more moderate temperatures. Most steam tunnels have large intake fans to bring in the fresh air and push the hot air out the back, and these may start without warning. Most active steam tunnels do not contain airborne asbestos, but proper breathing protection may be required for other respiratory hazards. Experienced explorers are very cautious inside active utility tunnels since pipes can spew boiling hot water or steam from leaky valves or pressure relief blow-offs. Often there are puddles of muddy water on the floor, making slips and falls a special concern near hot pipes.

Steam tunnels have generally been secured more heavily in recent years due to their frequent use for carrying communications network backbone cables, increased safety and liability concerns, and perceived risk of use in terrorist activities.