Question: "Could I Leave You?" was a song in Follies, a musical concering what?

Context paragraphs:
The Fabulous Palm Springs Follies: The Fabulous Palm Springs Follies was a Ziegfeld Follies style dance and musical review show that played at the historic Plaza Theatre in Palm Springs, California, United States, seasonally from November to mid-May.  The Follies was founded in 1990 by Riff Markowitz and Mary Jardin.  Impresario Markowitz also served as the show's managing director and emcee.  The show was often credited with helping to revitalize and maintain the downtown area by bringing in patrons from around the globe.  The Follies was unique in that it only featured performers 55 and older and holds Guinness World Records for this claim to fame.  It was the subject of a short documentary titled "" which was nominated at the 70th Academy Awards for Best Short Subject Documentary.  A segment that aired on Seattle television station KOMO-TV that featured the Follies received an Emmy in 1997.  The shows attracted approximately 170,000 attendees yearly.  On June 5, 2013, co-founders Markowitz and Jardin announced they would close the Follies on May 18, 2014.

Follies: Follies is a musical with music and lyrics by Stephen Sondheim and a book by James Goldman.  The story concerns a reunion in a crumbling Broadway theatre, scheduled for demolition, of the past performers of the "Weismann's Follies", a musical revue (based on the "Ziegfeld Follies"), that played in that theatre between the World Wars.  It focuses on two couples, Buddy and Sally Durant Plummer and Benjamin and Phyllis Rogers Stone, who are attending the reunion.  Sally and Phyllis were showgirls in the Follies.  Both couples are deeply unhappy with their marriages.  Buddy, a traveling salesman, is having an affair with a girl on the road; Sally is still as much in love with Ben as she was years ago; and Ben is so self-absorbed that Phyllis feels emotionally abandoned.  Several of the former showgirls perform their old numbers, sometimes accompanied by the ghosts of their former selves.  The musical numbers in the show have been interpreted as pastiches of the styles of the leading Broadway composers of the 1920s ands '30s, and sometimes as parodies of specific songs.

Ziegfeld Follies of 1936: The Ziegfeld Follies of 1936 is a musical revue with lyrics by Ira Gershwin, music by Vernon Duke and sketches by Gershwin and David Freedman.  The Ziegfeld Follies were a series of revues presented from 1907 through 1931, 1934, 1936, 1943, and 1957.

Could I Leave You? (song): "Could I Leave You?"  is a song written by Stephen Sondheim for the 1971 musical "Follies" for the character Phyllis.

Ziegfeld Follies (film): Ziegfeld Follies is a 1946 American musical comedy film released by Metro-Goldwyn-Mayer and directed by Lemuel Ayers, Roy Del Ruth, Robert Lewis, Vincente Minnelli, Merrill Pye, George Sidney and Charles Walters.  It stars many of MGM leading talents, including Fred Astaire, Lucille Ball, Lucille Bremer, Fanny Brice (the only member of the ensemble who was a star of the original Follies), Judy Garland, Kathryn Grayson, Lena Horne, Gene Kelly, James Melton, Victor Moore, William Powell, Red Skelton, and Esther Williams.

Fox Movietone Follies of 1929: Fox Movietone Follies of 1929, also known as Movietone Follies of 1929 and The William Fox Movietone Follies of 1929, was a black-and-white and color American musical film released by Fox Film Corporation.

Rock Follies: Rock Follies, and its sequel, Rock Follies of '77, is a musical drama shown on British television in the 1970s.  The storyline followed the ups and downs of a fictional female rock band called the "Little Ladies" as they struggled for recognition and success.  The series starred Rula Lenska, Charlotte Cornwell and Julie Covington as the Little Ladies, with support from Emlyn Price, Beth Porter, Sue Jones-Davies, Bob Hoskins, Stephen Moore, Derek Thompson, Denis Lawson and Little Nell among others.  The series was made with a very low budget for Thames Television, with a style inspired by fringe theatre.

Mark Rodenhauser: Mark Todd Rodenhauser (born June 1, 1961 in Elmhurst, Illinois) is a former American football center who played 13 seasons in the National Football League with seven different teams.  He played college football at Illinois State University.  He was selected by the Carolina Panthers in the 1995 NFL Expansion Draft.  Rodenhauser started his football career with the Chicago Bruisers of the Arena Football League.  He also made an appearance in the popular series Football Follies, in the 21st Century Follies DVDs, where he could snap a football a full length of a basketball court.

Glorifying the American Girl: Glorifying the American Girl is a 1929 American Pre-Code, musical comedy film produced by Florenz Ziegfeld that highlights Ziegfeld Follies performers.  The last third of the film (which was filmed in early Technicolor) is basically a Follies production, with cameo appearances by Rudy Vallee, Helen Morgan, and Eddie Cantor.

Our Gang Follies of 1938: Our Gang Follies of 1938 (later reissued as simply "Follies of 1938") is a 1937 American musical short subject, the 161st short subject entry in Hal Roach's "Our Gang" ("Little Rascals") series.  Directed by Gordon Douglas as a sequel to 1935's "Our Gang Follies of 1936", the two-reel short was released to theaters on December 18, 1937 by Metro-Goldwyn-Mayer.

Supporting paragraphs: Could I Leave You? (song) Follies
Answer: a crumbling Broadway theatre