Significant to the Commissioners' Plan of 1811 was the fact that Green was an outspoken critic of the grid. In 1867, he convinced the state legislature to give his Central Park Commission the power to make changes in the grid above 59th Street. However, even though few streets in that area had been laid out yet, property lines conformed to the grid, making sweeping changes to it difficult to achieve. Green was able to take advantage of a high ridge and create Morningside Park and Morningside Drive, and also created Riverside Park along the Hudson River; both parks were designed by Olmsted and Vaux. Green also laid out a broad Boulevardnow Broadwayup the center of the West Side.