Where can you find Manhattan’s longest road not taken? Find out on an urban hike through Upper Manhattan to the High Bridge. Completed in 1848, the city’s oldest bridge – a 1,450-ft. span, 100 feet above the Harlem River – was once the crowning flourish of a “herculean” fresh water supply system from Croton-on-Hudson. Though the Old Croton Aqueduct (OCA) trail forms one of the most delightful nature walks through several towns in neighboring Westchester County, it languishes in plain sight here in Manhattan. Stroll its route with Columbia University Community Scholar Eric K. Washington to discover many compelling diversions of the OCA trail, as it wends through West Harlem and Washington Heights. Some highlights may include such sites as the 19th century Carmansville district; new Sugar Hill Apartment & Museum complex; John T. Brush staircase; Morris-Jumel Mansion; and the urban wilderness path over Coogan’s Bluff that culminates at the historic High Bridge. Advisory: this rustic hike requires stepping over and upon rock outcroppings and mounting a steep flight of steps to leave the High Bridge.