He is best-known for his design of New York’s Central Park, but he is truly the father of the science of forestry management.
When George Vanderbilt purchased the 125,000 acres that would ultimately be the Biltmore estate, that land had been almost completely clear cut from the timber industry. Virtually every tree you see in that area south of Asheville was planted by Olmsted.
Olmsteds parks and thoroughfares basically set the layout for the entire North Side of the city of Buffalo.
Then 1950s and 60s progressives and Albany bureaucrats destroyed his vision - and entire swaths of the city - by putting expressways and overpasses through the heart of his parks and grand boulevards.
True genius
I looked up Eaton Hall and can see why he was inspired:
https://www.flickr.com/photos/24151047@N05/9388647640
https://www.flickr.com/photos/24151047@N05/9385938011/in/photostream/