In this series for T, the author Reggie Nadelson revisits New York institutions that have defined cool for decades, from time-honored restaurants to unsung dives.

On Sunday nights, when the house band plays jazz at the Ear Inn, a bar over by the Hudson River on Spring Street, the whole building shakes. In the little apartment upstairs — once the home of the Ear’s first proprietor and now used by the current owners for occasional gatherings — old Dutch gin jugs shudder, thick glass Champagne bottles rattle, and 18th-century apothecary flasks clink. But then this building, with its sloping floors and death-defying stairs, went up some time around 1770. It has housed a bar continuously since 1817. In its early days, water lapped at the front door, which was then just four feet from the river.

The Ear is an amiable place: good music, good company, good drinks and food. Waves of customers come and go throughout the day — including tourists, of course. When I visit in October, a woman remarks in a German accent, “My book says this is the last real place in New York.” At lunchtime, there are editors who come from the Penguin Books office around the corner, as well as a few locals, some execs from the UPS outpost across the street. Then the cocktail crowd comes: the groups of 20-somethings who gather on the sidewalk in good weather and the residents of the neighborhood’s shiny new condos.