By the 1830s, Manhattan's water supply was a public health catastrophe. Wells ran brackish, rivers were fouled, and cholera epidemics swept the city with terrifying regularity. The solution was ambitious: a forty-one-mile aqueduct system channeling water from the Croton River in Westchester County all the way to Manhattan's reservoirs. The most dramatic engineering challenge lay at the Harlem River, where the aqueduct needed to cross a valley 620 feet wide and more than a hundred feet deep. The bridge was proposed in 1839, and the design fell to John B. Jervis, the Croton Aqueduct's chief engineer, with a young James Renwick Jr. -- who would go on to design St. Patrick's Cathedral -- contributing to the plans. Water first flowed across the bridge in May 1848, carried through a pair of thirty-three-inch pipes beneath an earthen embankment that protected them from freezing.

The original fifteen semicircular stone arches gave the bridge the profile of something ancient, a piece of Rome transplanted to the Bronx. But beauty created problems. The five arches spanning the river left narrow gaps for barges and boats, with clearances sometimes under eight feet. Ship captains and river commerce interests agitated for demolition as early as the 1910s. In 1923, the city approved tearing the bridge down entirely, but a counterproposal won out: replace only the five river arches with a single steel span of 450 feet. The reconstruction, completed in 1928, preserved the ten surviving stone arches on either shoreline while opening the river to navigation. The hybrid result -- ancient stone meeting early-twentieth-century steel -- gives the bridge its distinctive split personality.

Water stopped flowing across the High Bridge in 1958, made redundant by newer infrastructure. By the early 1970s, safety concerns prompted the city to close the bridge to all traffic, and for more than forty years it sat abandoned, rusting quietly between Highbridge Park in Manhattan and the Highbridge neighborhood of the Bronx. The gatehouses at each end deteriorated. The High Bridge Water Tower, which once pumped water to the Highbridge Reservoir, still stood at the Manhattan end but served no function. Meanwhile, the neighborhoods on both sides of the river -- communities that could have used a pedestrian connection -- were walled off from each other by a structure that had once linked them.

After years of community advocacy and planning, restoration work began in 2013. On June 9, 2015, the High Bridge reopened to pedestrians and cyclists for the first time in over four decades. The rehabilitation preserved the bridge's landmark character -- its stone arches, its ironwork, its sheer vertical drama over the river -- while making it safe for modern use. Walking across it today, you pass from Manhattan into the Bronx at treetop height, with the Harlem River far below and the Alexander Hamilton Bridge and Washington Bridge visible to the north. The geology beneath you tells its own story: the valley floor is Inwood marble, softer than the Manhattan schist on one side or the Fordham gneiss on the other, which is why the river carved its course here in the first place. The bridge that once delivered water to a thirsty city now delivers something else -- a quiet corridor between two boroughs, 140 feet above the current.