The Hudson River Greenway is the longest greenway in Manhattan, running along the West Side, from Dyckman Street in the north to Battery Park in the south, mostly through Riverside Park and Hudson River Park. A gap in West Harlem was filled in early October 2008 with the opening of the Harlem Piers bike lane. A roughly 10-block detour in the west 80s, where a walkway had crumbled into the river in the late 20th century, was eliminated on May 20, 2010, when the rebuilt section of greenway was opened.