The legit industry trade org, the Broadway League, classifies 40 venues as Broadway houses, and a look at their stats offers a bird’s-eye view of physical Broadway.The three biggest landlords on the White Way are the Shubert Organization (17 theaters), the Nederlander Organization (nine) and Jujamcyn Theaters (five). The Shubert brothers started in the biz in upstate New York and came to Broadway in 1900. Many of the houses they built are still in use. David T. Nederlander began his theater operations in Detroit 100 years ago. Descendants of the founder still run the org, which also operates Los Angeles venues the Greek Theater and Staples Center Arena. Jujamcyn Theaters was founded in 1956 by William McKnight. In 2005, Jujamcyn’s president, Rocco Landesman, bought the company from Mc-Knight’s heirs. Landesman sold half to producer Jordan Roth, who assumed control in 2009 when Landesman decamped for the top job at the National Endowment for the Arts. Foxwoods Theater, operated by Live Nation (which also runs Gotham’s Roseland Ballroom and the Hollywood Palladium), is home to “Spider-Man: Turn Off the Dark,” while another Broadway house belongs to Disney — the New Amsterdam Theater, which currently houses the kid-friendly tuner Mary Poppins. Almost 100 years ago, that stage was home to the Ziegfeld Follies.