Yvonne’s isn’t exactly hidden—its presence in Downtown Crossing is announced by a neon-lit sign—but the entrance is still something of a head-fake. Would-be revelers encounter what appears to be a disused beauty salon, before a host leads the way to reveal a sprawling supper club. The hidden gem features two bars and Gilded Age details aplenty: the molded ceilings and carved wooden bar—circa 1886—are preserved from its tony previous tenant, Locke-Ober. The cocktail menu features old-school standards like the Ward 8, a rye-based sipper that was invented at Locke-Ober; along with house creations, large-format cocktails, and one of the best Espresso Martinis in Boston.

Among industrial buildings and through a couple of mysteriously marked doors, cocktail fans will find Bully Boy’s Roxbury distillery and a tiny tasting room. The latter could pass for a Mad Men-era cocktail lounge—until you glimpse the working stills from behind the bar’s windows. The chic, dimly lit tasting room serves up freshly made spirits by the flight and in cocktails both classic and original. Here’s another secret you’ll want to be in on: Ask the bartender about the rotating draft cocktail options and the oft-changing barrel-aged cocktail. 

Down a nondescript hallway in a nondescript building, the entry into Backbar is an ironic introduction for a cocktail bar buzzing with creativity. The inventive drinks at this hidden gem are top-notch, but Backbar never takes itself too seriously. Just look at the always-changing themed cocktail menus that riff on everything from Lord of the Rings to world maps, bears, and even Encanto. Another thing that makes this underground bar so special? Union Square neighbors Field & Vine and Littleburg provide a food menu of snacks with seasonal ingredients.