As heady as champagne, Franz Lehár’s classic operetta The Merry Widow draws us into the opulent Paris of the legendary Maxim’s in this first-ever Boston Lyric Opera production. Featuring a lush design and a new book by director Lillian Groag, The Merry Widow is set in 1913 Paris in the last moments before the glittering City of Light would be overshadowed by war—a party at the end of the world.