You’d think the Vanderbilts and Rockefellers of the world would have been happy to entertain in their lavish mansions. But in the second half of the 19th century, as trains and cars replaced horses and buggies, American society extended how far it was willing to go for a good party.

Enter the grand hotels of the Gilded Age. They had dark bars for trysts and business deals, accommodations with chandeliers and silk linens and restaurants that served delicacies on fine china and crystal. “Had,” of course, is the operative word: Few of these venues remain.

Now, developers are turning their attention to the remaining socialite playgrounds of yesteryear. “Hotels with rich histories make guests feel like they are part of something meaningful,” said David Roedel, who helped redevelop Hotel Saranac in New York’s Adirondacks.

And while it’s challenging to modernize a property such as Blantyre, a fantastic castle in the Berkshires, these legendary assets are tempting entrepreneurs because no one would invest in building something so lavish now. “There is no way these historic properties can be replicated today and be viable business opportunities,” says Blantyre’s owner, Linda Law.

Here are the most exciting recent historic renovations.

The Four Seasons Hotel at the Surf Club, Miami

The history: The Surf Club opened with a debauched New Year’s Eve gala in 1930 and never stopped partying. Elizabeth Arden would throw Champagne-fueled fashion shows by the pool. Winston Churchill took two poolside cabanas: one for painting and one for sleeping off hangovers. Frank Sinatra and other members of the Rat Pack saw it as a place to do whatever they wanted, far from prying eyes.

The 2.0 version: In 2017, the Surf Club was reborn as a Four Seasons, with whitewashed rooms and a Champagne bar in the former clubhouse. A Thomas Keller restaurant is coming soon. But the five second-floor Cabana Studios would still be recognizable to their former occupants: Elizabeth Taylor, Tennessee Williams and Dean Martin.

Hotel Saranac, Lake Saranac, N.Y.

The history: In the Roaring ’20s, you either owned a Great Camp in Lake Saranac or hacked it by staying at one of 13 nearby hotels. Only the Hotel Saranac remains. It’s where feminists rallied in favor of Prohibition while speakeasy barmen slung cocktails.

The 2.0 version: It took three years and $35 million to restore the hotel. Now many locals come in for a Negroni in the great hall, which has a painted wooden ceiling inspired by Florence’s 14th-century Davanzati Palace. Guests can also mail postcards from an original letterbox or warm up around rooftop fire pits with views of the Hudson Valley.

The U.S. Grant, San Diego

The history: This hotel was built in tribute to the 18th president, but Woodrow Wilson and John F. Kennedy loved to stay at this San Diego icon for its unparalleled glitz and five-star hospitality. It was so popular with commanders in chief that a radio station was added to the hotel for national broadcasts. During Prohibition, the hotel’s co-owner used connections in Mexico to smuggle in alcohol via underground tunnels.

The 2.0 version: A $13 million renovation was completed this year. Suites still have the signature sparkling chandeliers and custom Yves Clement drip-painted headboards.

The Adelphi Hotel, Saratoga Springs, N.Y.

The history: Think of Saratoga Springs as the Hamptons of the late 19th century: Everyone from Cornelius Vanderbilt to gangster-turned-congressman John Morrissey came here for the soothing natural springs and velvet-clad bars. At the center of it all was the Adelphi.

The 2.0 version: The wall behind the reception area is made of glass plates and ashtrays from the original property. The suites are exquisite, with reclaimed gilded mirrors and modern touches such as heated bathroom floors. And the original grand staircase now leads to Morrissey’s bar and restaurant, where you can order platefuls of oysters with yuzu mignonette.

Blantyre, Lenox, Mass.

The history: In the late 1890s, British gentleman Robert Paterson decided to clone his mother’s ancestral home in Scotland on 220 acres in the Berkshires. When completed, the castle became the backdrop for black-tie garden parties and salacious supper clubs.

The 2.0 version: When the property reopens this month, it will have America’s only Dom Perignon Champagne lounge, a spa in the former potting shed, and a croquet court. Head to the Conservatory to find one important nod to the hotel’s past: drinks served in William Yeoward crystal.

The Oasis at Death Valley, Calif.

The history: In America’s hottest, driest national park, the Pacific Borax Mining Co. built a hotel in 1927 in an oasis with natural springs. Then the owners added a spa and lush gardens, and Hollywood stars such as Clark Gable and Ronald Reagan started coming. In 1977, the inn accommodated the entire cast of “Star Wars,” which was filmed nearby.

The 2.0 version: On Feb. 1, the Oasis at Death Valley welcomed its first guests after a six-year, multimillion-dollar renovation. A new bar with terra-cotta floors is lined with paintings that tell the area’s story, and 22 Spanish-style casitas were added. Lounge around the spring-fed pool and ask for a milkshake made with fruit from the hotel’s date groves. Said general manager Dominie Lenz, “We get to live up to the grandeur of this space — and welcome people to a destination Americans forgot existed.”