New Yorkers are a tough audience. William Charles Macready learned the hard way. On May 10, 1849, the British Shakespearean actor was scheduled to perform the title role in “the Scottish play” at the Astor Place Opera House. Outside, nearly 15,000 fans of American stage idol Edwin Forrest gathered. The rivalry between the English aristo and the working-class hero had already stopped several performances here and abroad—hisses, catcalls, eggs and fruit thrown onstage. But the producers, adamant that the show must go on, asked for police protection, boarded up the windows, and barricaded the doors. Mayor Caleb Woodhull, a week into his term, sent 250 officers and put the National Guard on alert. It wasn’t enough. Hundreds of Bowery B’hoys gang members pelted the cops with rocks, bricks, and paving stones lifted off the street. The police retreated into the building as stones crashed through the windows, hitting the audience. By then not even two divisions of the 7th Regiment could quell the mob. And so for the first time, U.S. troops fired on Americans, killing at least 22. Over 100 militia, police, and civilians lay wounded. Unable to shake the bad press surrounding the second bloodiest riot in the city’s history, the opera house closed. Now it’s a Starbucks.