It’s been a mild winter so far in New York, and with the first onset of below-freezing temperatures, city folk are donning their heavy jackets and gloves. And while the winds whipping around the glass and steel towers of Manhattan might feel as if it’s as cold as it’s ever going to be, consider a century ago when temperatures were low enough to freeze the East River from the banks of Brooklyn to the Manhattan waterfront, still two different cities at the time, providing thrill-seeking pedestrians with an instant new crossing years before the Brooklyn Bridge was built.

The above view was engraved in 1871 and titled, “Crossing the East River on the Ice Bridge,” depicting dozens of New Yorkers walking across what would normally have been a busy maritime thoroughfare. While such a natural feat seams unlikely today, Gothamist has collected clippings to show that the phenomenon was known to occur around once a decade on the East River during the 19th century and there have been reports of similar frozen-river bridges along the Mississippi and Ohio Rivers as well. For instance, in 1851, an estimated 15,000 pedestrians, horses, and sleighs crossed the frozen river.