2A close-up of the model for “Scream,” 1978. 9A stage model depicting a haunted wood. Date and production unknown. 3A 19th-century toy theater stage set of “Whittington and His Cat,” made by Benjamin Pollock of London, circa 1880. 1A miniature stage set for “Scream,” 1978, at the Alley Theatre, Houston. 5A detail from a model stage set for “The Magic Flute,” a Lowell House Opera done in both 1975 and 1992. Date of model unknown. 4Another view of the Pollock set of “Whittington and His Cat.” Toy theaters were popular home entertainment in 19th-century Europe. 13Another view of “Artist Descending a Staircase,” a murder mystery involving an artist’s fatal tumble down a staircase. 11A model for “Sensations,” a 1970 off-Broadway rock ‘n’ roll version of “Romeo and Juliet” starring John Savage and Judy Gibson. 15From a stage set titled “The Promised Land,” designed by Kenneth Dresser. Venue and date unknown. 8Detail, “Timbuktu!” stage set. 6Detail, model for a Lowell House Opera production of “The Magic Flute.” 10A model by Joan Ferenchak for “Figaro,” a 1978 student production on the Loeb Drama Center’s mainstage. 12A half-inch-scale model for “Artist Descending a Staircase,” a 1972 Tom Stoppard radio play first adapted for the stage in 1989. The Harvard Theatre Collection is among the oldest and largest of its kind in the world. Within the climate-controlled subterranean reaches of Houghton Library are shelves, drawers, and boxes full of theater, dance, movie, and music items.By one estimate, the 113-year-old collection’s 22,000 linear feet of holdings, if stacked vertically, would be 3 miles high. There are 4 million playbills and programs, along with countless: libretti, sheet music, tickets, posters, rare books, scores, photographs (about 1.2 million), oil portraits, figurines, and sculptures (about 600). There are even eight boxes of Javanese metal puppets.The collection’s “realia,” or personal effects, include a piece of 100-year-old wedding cake and a tin of decades-old butter cookies. “They look way too good,” said acting curator Susan Pyzynski.Among the riches, perched on file cabinets, are a few dozen model stage sets, mockups made of paper, metal, plastic, and wood that in many cases are from long-ago Harvard student productions. Some look fresh, including the tiny figures and bright sun umbrellas that modeled the musical “Timbuktu!” a few decades ago.Some are fragile. “They’re not exactly made to last,” offered Pyzynski. Still others hold time in a bottle. The set of “Sensation!,” a rock ’n’ roll remake of “Romeo and Juliet” from 1970, features a tiny longhaired figure wearing a vest and bell bottoms. Tempus fugit.There are miniatures sets of stage classics (“The Magic Flute,” “Evita”). Some are mysteries awaiting explication by theater scholars, like the unlabeled, intricate model of deep haunted woods, right out of a fairy tale. Still other models call back the earliest days of theater. For one, the collection has several scaled-down renderings of Shakespeare’s Globe Theater. Said Pyzynski, “You can never have too many of those.” 7A half-inch-scale model of the marketplace scene from “Timbuktu!” Venue and date unknown. 14From the model for “Artist Descending a Staircase,” a title inspired by Marcel Duchamp’s 1912 painting “Nude Descending a Staircase, No. 2.” 16Detail from “The Promised Land.” 17A model stage set for Otto Nicolai’s 1849 opera “The Merry Wives of Windsor,” produced in 1988 by the Lowell House Opera and inspired by the 1602 comedy by William Shakespeare. 18A detail from Lowell House Opera’s 1988 “The Merry Wives of Windsor.” 19Detail from a model of Shakespeare’s Globe Theatre (1599-1613), constructed in 1953 by John Ronayne and John Mills and based on a design by English artist C. Walter Hodges. 20A detail from the 1953 model of Shakespeare’s Globe Theatre, later realized as a full-scale modern reconstruction completed in 1997.