Few small American businesses last a decade let alone 160 years without changing a thing.
McSorley's Old Ale House in New York's East Village is the the very rare exception to that rule. And the secret to the bar's long-term success may have everything to do with two traditions.
The first is that the Irish bar was open only to men from its 1854 founding until a 1970 ruling that all New York City businesses must serve both female and male customers. The second might be considered a core business strategy. McSorley's house ale in two variations—"light" and "dark"—are the only drinks available on tap.
In 1956, NBC's "Today" paid a visit to the bar's East 7th Street location for a live report. In front of a McSorley's facade looking much the same as it does nearly six decades later, correspondent Paul Cunningham warns of a "dastardly deed about to be committed." A local building project threatened the existence of the tavern, then just two years past its centennial.
(Read more: Cramer: Could you use a good stiff drink?)
Cunningham apologizes for hesitating before leading the camera across the bar's threshold, sheepishly explaining that "in one century and two years, no women have ever been permitted to come into McSorley's Old Ale House."
—By CNBC's Katie Kramer.