Built by a lawyer in 1843 as a country estate, the 28-acre, riverside Wave Hill served the needs of the wealthy and connected until it became a city park in 1960. Other guests have included Theodore Roosevelt and Mark Twain. There are soaring views of the Hudson and a cafe in the stone mansion that serves as the park’s centerpiece. From the Riverdale Metro-North station it’s a 15-minute walk uphill, or catch the free van service from the station, provided by Wave Hill.