What Waits Below is a science-fiction adventure film (initially released under the title "Secrets of the Phantom Caverns") released in 1984.
 Directed by Don Sharp, produced by the Adams Apple Film Company, the film runs for 88 minutes and starred Robert Powell, Timothy Bottoms, and Lisa Blount.
 The tagline for the video release of the film was "Underground, no-one can hear you die".
Neal P. McDonough (born February 13, 1966) is an American film, television, actor and voice actor, known for his portrayal of Lieutenant Lynn "Buck" Compton in the HBO miniseries "Band of Brothers" (2001), Deputy District Attorney David McNorris on "Boomtown" (2002–2003), Sean Cahill on "Suits", Robert Quarles on "Justified", and Dave Williams on ABC's "Desperate Housewives" (2008–2009).
 He also appeared in films such as "Minority Report", "Walking Tall", "Red 2", "", "Traitor", and as Dum Dum Dugan in various Marvel Cinematic Universe films and TV series.
 He appeared as Damien Darhk on "Arrow", and in "Legends of Tomorrow", as well as voicing a variety of comic superheroes and villains in a number of animated films and video games.
Ben McKenzie (born Benjamin McKenzie Schenkkan; September 12, 1978) is an American actor.
 He is known as Ryan Atwood  in the television series "The O.C." and as Ben Sherman in "Southland".
 He appeared in the films "Junebug" and "88 Minutes".
 His first starring role in a feature film was in the 2008 indie release "Johnny Got His Gun".
 Since 2014, McKenzie has been starring as James Gordon in the television series "Gotham".
Julian Christopher (born November 7, 1944) is an American actor.
 He is best known for his roles in various films and television series from the 1970s to the present, including The Magician, with Bill Bixby.
 His most notable appearances were in "Cool Breeze, , Elysium" and "88 Minutes".
The Magician is a 1926 horror film directed by Rex Ingram about a magician's efforts to acquire the blood of a maiden for his experiments to create life.
 It was adapted by Ingram from the novel "The Magician" by W. Somerset Maugham.
 It stars Alice Terry (the director's wife), Paul Wegener and Iván Petrovich.
 Critic Carlos Clarens wrote that it was "perhaps the most elusive of lost films."
 However, since the time Clarens wrote this, various prints of the film have surfaced.
 Some have screened at independent movie festivals from 1993 onwards, and the film has also been shown on Turner Classic Movies.
 It remained commercially unavailable being released on DVD in the Warner Brothers Archive Collection in 2011 (with a running time of 88 minutes).
Stephen Frederick Schneck (born 1953) is an American Catholic activist, associate professor at The Catholic University of America (CUA), and former Director of CUA's Institute for Policy Research and Catholic Studies.
 A public speaker and lecturer, Schneck is a frequent source of media analysis on issues involving Catholicism and public policy.
 He was chair of the Department of Politics from 1995-2007 and Acting Undergraduate Dean of the School of Arts & Sciences in 1988.
 From 2012-2013 he was appointed as the Acting Dean of the National Catholic School of Social Service at Catholic University.
88 Minutes is a 2007 American thriller film directed by Jon Avnet, and starring Al Pacino, Alicia Witt, Leelee Sobieski, William Forsythe, Deborah Kara Unger, Amy Brenneman, Neal McDonough and Benjamin McKenzie.
 Filming began in the Vancouver area on October 8, 2005, and wrapped up in December 2005.
 In 2007 the film was released in various European countries.
In physics, a sign convention is a choice of the physical significance of signs (plus or minus) for a set of quantities, in a case where the choice of sign is arbitrary.
 "Arbitrary" here means that the same physical system can be correctly described using different choices for the signs, as long as one set of definitions is used consistently.
 The choices made may differ between authors.
 Disagreement about sign conventions is a frequent source of confusion, frustration, misunderstandings, and even outright errors in scientific work.
 In general, a sign convention is a special case of a choice of coordinate system for the case of one dimension.
Gary Scott Thompson (born October 7, 1959) is a screenwriter, television producer, and director.
 Thompson is most notable for his work on "The Fast and the Furious" starring Vin Diesel, the sequel "2 Fast 2 Furious", "Hollow Man" with Kevin Bacon, "Split Second", "88 Minutes", starring Al Pacino, and "K-911" and "".
Chamber Music is a composition in three sections for female voice, clarinet, cello and harp by the Italian composer Luciano Berio.
 It is a setting of three poems from the collection of poetry "Chamber Music" by James Joyce, whose work was to be a frequent source for Berio.
 The songs were composed in 1953, and show the influence of Luigi Dallapiccola with whom Berio had studied in 1952 at the Tanglewood Music Center.

Question: What comic universe is a frequent source of work for an American actor who starred in the film 88 Minutes?
Answer: Marvel Cinematic Universe