Storm King Art Center is an enormous outdoor sculpture garden in Cornwall, New York open from April through early December. The grounds of Storm King are vast (500 acres!) and completely outdoors. While there are trams, a visit to Storm King includes a lot of walking, some of it up hills. So come prepared to sweat a bit.
Even a casual fan of art will be blown away by the sheer size and grandness of the sculptures at Storm King. Kids will love running around and spotting new art on top of hills and in the distance. Many pieces are part of Storm King's permanent collection, but many others come and go. Before you visit, spend some time with the grounds map to figure out what sculptures you most want to see - among other things, the map indicates which sculptures are interactive/able to be touched.