For those of us at Air Mail, Keens Steakhouse is a crucial part of the must-know restaurants list. After all, our founder, Graydon Carter, takes his family there for a holiday dinner every year. Nathan King, our former deputy editor, chose it to celebrate his marriage, and the editorial team once gathered there for a Christmas lunch. What’s not to love? The steaks are excellent, and the sides unmissable. But its history and atmosphere are the real draw. A lone survivor of the now-shuttered Herald Square Theater and late 19th-century Broadway scene, Keens greets diners with leather couches, dark wood paneling, framed paintings, and patterned rugs. Plus, the restaurant owns the world’s largest collection of churchwarden pipes. —Jeanne Malle