Organized crime, crime carried out systematically by formal criminal organizations

London Underground, a metro system that covers the Greater London area

Underground rapid transit system, urban railway

Linkin Park Underground, the official fan club of the band Linkin Park

Underground (1995 film), directed by Emir Kusturica

Underground city, a network of tunnels that connect buildings, usually in the downtown area of a city

Need for Speed: Underground 2, the sequel to Need for Speed: Underground

Tony Hawk's Underground 2, the sequel to THUG by Activision Studios

Underground economy, commerce that is not taxed

Karst topography, a landscape of distinctive dissolution patterns often marked by underground drainages

Tony Hawk's Underground, a video game published by Activision Studios

Underground press, the alternative print media in the late 1960s and early 1970s

Underground comix, small press or self-published comic books that began to appear in the US in the late 1960s

Need for Speed: Underground, a video game published by Electronic Arts

Resistance movement, dedicated to fighting an invader or the government

UK underground, a 1960s countercultural movement in the United Kingdom

Underground (role playing game), a satirical role playing game released by Mayfair Games in 1993

"Underground" (stories), a collection of biographical short stories by Murakami Haruki

TCM Underground, a late-night cult film showcase airing on Turner Classic Movies

Underground Resistance, a musical collective from Detroit, Michigan

Underground culture, a term to describe various alternative cultures

"Underground" (Stargate Atlantis), a Stargate Atlantis television series episode

Underground living, living below the ground's surface

Underground film, cinema outside the commercial mainstream

Underground hip hop, a style of hip hop music

"Underground" (song), a 1986 single by David Bowie featured in the film Labyrinth

Medal of Honor: Underground, the second in the Medal of Honor series by EA Games

Underground (1928 film), directed by Anthony Asquith

Underground (Thelonious Monk album), a 1967 jazz recording by Thelonious Monk

Underground (book), a 1997 book by Suelette Dreyfus reconstructing the actions of a group of hackers

"Underground" (Ben Folds Five song), a 1995 song by Ben Folds Five

Underground (Electric Prunes album), a 1967 album by The Electric Prunes

Underground music, music that has a certain following despite a moderate commercial success

Underground (Keaggy album), a 1983 album by guitarist Phil Keaggy

The Underground (TV series), a sketch comedy show starring Damon Wayans.

Underground (Analog Pussy album), a 2001 album by Analog Pussy

Underground (1941 film), directed by Vincent Sherman

Underground (soundtrack), soundtrack to the Emir Kusturica film by Goran Bregović

Underground Operations, a Toronto-based independent punk rock record label

The Underground (concert venue), a Christian-affiliated concert venue, operated in the Greater Cincinnati area

Underground (novel), a 2006 Australian novel by Andrew McGahan

Underground Atlanta, a nightspot in Atlanta, Georgia