Runners often struggle with the Queensboro Bridge, First Avenue in Manhattan and the homestretch of the run. Adrenaline and block party vibes have a way of carrying runners during the first half of the marathon, but eventually the slog of running 26.2 miles starts to kick in. The New York City Marathon devolves into a Greek tragedy for ill-prepared runners at an unsuspecting half-mile stretch of the Upper East Side — where.