Riverside Park looking north from 145th Street. Besides the landscaping, paths, ball fields, and trees, you can also see the "rip-rap wall" of rocks piled up at the riverbank to prevent erosion[1]. All New Deal work. The Henry Hudson Parkway too, of which you can see a tiny bit on the far right. The rocks came from newly excavated railway bed between 72nd and 129th Streets[2].

References:

1. NYC Parks Dept press release of October 11, 1937: “The rocky shore of Fort Washington Park is being developed for the purpose of restoring and preserving its natural scenic beauty as an area for passive recreation.”
2. Caro, Robert A., The Power Broker - Robert Moses and the Fall of New York, Vintage Books (1974), p.530.
3. New Deal Assistance in NYC Parks Department Projects, 1934-43.