Trekking western Long Island, I feel strangely at home. Not a surprise, given my great-grandfather, had an estate nearby. Circa 1890's during the Gilded Age, he built a 660-acre estate complete with a 300-foot horse stable, a chapel, and quarters for staff. The residence was so large that, when the property was later re-developed and subdivided, four buildings were separated from the main complex and remain today.
Wheatly Estate - a fascinating article from Old Long Island
Long Island's cities and villages are all quite accessible via Long Island Railroad. Get off at almost any stop and you'll have a history lesson. We had one at Garden City. Manhattan-sized Cathedral of the Sacrament. Built to the memory of Alexander Turney Stewart, the Cathedral of the Incarnation is the only cathedral in the United States funded by a single person, and the only one that is built in memory of a single individual
Garden City Hotel is not as Grand as it was in 3 previous iterations. But still a beautiful setting, and a walk down any street yields lat 19th and early 20th century mansions.