She broke off, laughing, to explain that she had come up to town from Tuxedo, on her way to the Gus Trenors' at Bellomont, and had missed the three-fifteen train to Rhinebeck.
--Edith Wharton, The House of Mirth
Okay, hands up, who's read The House of Mirth? Because this is exactly the type of house Wharton's writing about. (Okay, not exactly, since the title is a metaphor, but you get the idea).

Seating herself on the upper step of the terrace, Lily leaned her head against the honeysuckles wreathing the balustrade....Beyond the lawn, with its pyramidal pale-gold maples and velvety firs, sloped pastures dotted with cattle; and through a long glade the river widened like a lake under the silver light of September.
Here's that view, from the mansion's back terrace:


Back in the day, there probably were cattle; the National Parks Service brochure says that Vanderbilt kept prize-winning livestock.
The first thing you see when you drive in the gate is this bridge.
It sets quite an impressive scene. It's a bridge that you might expect in a public park, but not at a private residence. But there's even more going on here. It's made of reinforced concrete, built less than ten years after the very first United States reinforced concrete bridge (Alford Lake bridge, Golden Gate Park in San Francisco). It echoes the technologically-modern house, which is hiding concrete and steel under its limestone facade.*
And as you drive over it, you hear the rush of water. A dam under the bridge, built to create the upstream pond, also conveniently creates a small waterfall complete with rushing water sounds. It's like a little mini testament to ego. You know, in case the house wasn't enough.
The grounds are landscaped with specimen trees, many of which I didn't recognize. And some were just photogenic. I liked the way this tree's leaves folded


and the spiny silhouette this tree embossed on the sky

and the way this one rooted along its trunk so many times it looks like the Loch Ness monster.

I'm glad I went, even though I missed the tour. Next year I'd like to take a few extra days to tour more of the Hudson Valley historic homes.
*National Parks Service brochure; American Building by Carl Condit.