The Preservation Society of Newport Country acquired the home in 1963 and turned it into a museum open to the public. Self-guided tours cost $25 per adult ticket and can be purchased on the Preservation Society's official website.

During the winter months, the mansion is only open to the public on Saturdays and Sundays, with daily tours restarting in mid-February.

William K. Vanderbilt was Cornelius Vanderbilt's grandson and heir to the family's railroad and steamship fortune during the Gilded Age. Alva Vanderbilt was a popular hostess in Newport.

When Alva Vanderbilt divorced her husband in 1895, she survived the scandal and kept Marble House and custody of their three children, Consuelo, William Kissam Jr., and Harold Stirling. She then married one of her neighbors in Newport, a financier named Oliver H.P. Belmont, in 1896.

After Belmont died in 1908, she became a leader in the women's suffrage movement, funding the National American Woman Suffrage Association and serving as president of the National Woman's Party.

"It would have been impossible to have used a pure white marble for the interior without having a mausoleum effect too cold for living comfort and joy," Alva Vanderbilt wrote of Marble House. "The soft gold brown fading off into delicate cream catches the sunlight by day or electric sparkle at night with a warm living glow."

The French doors in the entryway stayed open during the summer to provide a cooling ocean breeze.

Alva Vanderbilt was born in Alabama and raised in France. Her French design sensibilities were evident throughout the house.

The walls were created from one solid slab of marble that was cut in half to create pieces with mirroring patterns, a technique called bookmatching.

Crafted from bronze and covered in gold, the chairs weighed 75 pounds each and required the help of a footman to be seated in.

The ribbed ceiling, stone mantlepiece, and wood floors were all imported from Paris.

Buying art collections "en bloc" was popular during the Gilded Age as a way to quickly acquire a status symbol instead of taking generations to build a collection.

The wooden bookcases, built in Paris by Allard and Sons, held books on architecture and European history that were original to the Vanderbilt family's collection.

"This room is really the epitome of the Gilded Age," Caitlin Emery, the research and interpretation coordinator at the Preservation Society of Newport County, said on the audio tour. "It is coated in gold and you have to imagine guests coming in on a summer evening with the sun going down. And the light picking up on all these gilded surfaces. The feel and the essence of the room would have been absolutely remarkable."

In 1895, the Vanderbilts hosted a ball to celebrate their daughter Consuelo Vanderbilt's engagement to Charles Spencer-Churchill, the ninth Duke of Marlborough. The party featured 300 guests and lasted until 5 a.m.

Consuelo Vanderbilt was secretly engaged to another man and resisted the arrangement, but she wrote that her mother "would not hesitate to shoot" her lover if she tried to run away with him.

"Alva wanted to secure for her daughter the one thing that money couldn't buy — a title," Emery said in the audio tour.

Theirs was a loveless marriage. After 26 years, Alva Vanderbilt testified that she had forced her daughter to marry the duke, which allowed her to receive an annulment in 1921.

The mezzanine level featured two private studies, one for William K. Vanderbilt and one for Alva Vanderbilt.

Consuelo Vanderbilt moved to Marble House when she was 15. She described her room as "austere," writing that her mother had picked out every piece of furniture and "forbidden the intrusion of my personal possessions," according to the audio tour.

The Vanderbilts would never have used the servant staircase or gone into the service areas.

When the Vanderbilts lived at Marble House, the Trophy Room was a set of two connected dressing rooms for Alva Vanderbilt and Consuelo Vanderbilt. The Preservation Society turned it into a room for Harold Vanderbilt's yachting trophies.

The carvings in the molding throughout the room featured nymphs and cherubs for a fairytale-like oasis.

The factory that made Alva Vanderbilt's original wallpaper is still in business in Lyons, France, and it kept the Marble House orders in its archives. In 1990, the Preservation Society ordered the exact same wallpaper from the factory to replace the room's existing fabric, which had faded to gold, according to the audio tour.

His bedroom was decorated in the French Neoclassical style. After he and Alva Vanderbilt divorced, William K. Vanderbilt moved to France with his second wife.

Marble House only had one guest bedroom because it was mainly built for family use.

The guest sitting room was furnished with 18th-century French art and furniture produced by Allard and Sons.

The stairs leading up to the rest of the house were locked to protect the Vanderbilts and their priceless possessions.

The Vanderbilts paid their French chef a salary of $10,000 per year, or around $375,000 in today's dollars.

The sink was made of a soft mineral called soapstone to prevent the Vanderbilts' silver from being scratched or damaged during washing.

Alva Vanderbilt hosted women's suffrage conferences at Marble House in 1904 and 1914.

She is quoted as saying in her speeches: "Just pray to God. She will help you."

A "Votes for Women" teapot cost $28 at the gift shop when I visited in August. The large plates cost $14.95 and the smaller plates retailed for $12.95.

Marble House is located along Newport's Cliff Walk, a scenic walking tour of the area's famous mansions.

Designed by Richard and Joseph Howland Hunt, the Chinese Tea House is now a café that offers refreshments and afternoon tea to Marble House visitors.

Imported from Europe, the trees can grow 35 to 45 feet wide.

Built during a time of economic and technological advancement, Marble House symbolized the beginning of a new era where women could leave loveless marriages with their reputations intact and fight for the right to participate in America's democracy.

In total, Frederick and Louise Vanderbilt spent $660,000 to build the home (more than $23 million in today's money) and $1.5 million (around $53 million today) to furnish it.

Frederick and Louise didn't have children. After Frederick's death in 1938, he left the house to Louise's niece, Margaret Van Alen. The Vanderbilts' neighbor in Hyde Park, President Franklin D. Roosevelt, then suggested preserving the estate by converting it into a national park.

The Vanderbilt Mansion opened to the public in 1940, according to the National Park Service.

The only way to see inside the mansion is through a guided tour with a park ranger.

Between January and May, the hourlong tours are offered daily at 10 a.m., 12 p.m., 2 p.m. and 4 p.m. A new summer tour schedule is posted before each season.

There are no reservations — $15 tickets are sold at the visitor center on a first-come, first-serve basis.

The Vanderbilts' largest home, the Biltmore Estate in Asheville, North Carolina, features 35 bedrooms, 43 bathrooms, and 65 fireplaces.

The Vanderbilt family also had homes in New York City, Rhode Island, and Massachusetts.

The building was designed by architects McKim, Mead & White and built by Norcross Brothers. The exterior is made of Indiana limestone.

The Vanderbilts used the home as a seasonal escape in the spring and fall. It has six floors and a total of 54 rooms, according to the National Park Service.

The oval-shaped entrance hall was furnished with green marble imported from Italy.

Unlike most residences at the time, the mansion had running water and electricity.

The office contained a private bathroom that led into his den.

The den included a small library of books and a moose head mounted to the wall.

The Vanderbilts hosted their first housewarming dinner party in May 1899, and only entertained about once per season.

The carpet measures about 20 by 40 feet.

Decorated with antique Renaissance furniture, the living room featured Circassian walnut panels on the walls.

Frederick and Louise had a permanent residence in Paris, which inspired the Louis XIV-style decor.

Vanderbilt butler Alfred Martin told the National Park Service that when the door to the salon was closed, "that was a sure indication that Mrs. Vanderbilt did not want to be disturbed."

The railing of the staircase was coated in velvet to make even climbing the stairs a comfortable, luxurious experience.

The second floor housed Frederick and Louise's bedrooms, as well as her dressing room and several guest rooms.

When I visited in January, the guest bedrooms were staged to appear the way they would have at that time of year. It took servants weeks to cover and uncover every item in the home with custom-made sheets.

In European palaces, railings around royal beds were utilized during daily ceremonies when a monarch woke up or during royal births. In Louise's bedroom, the railing was merely a decorative homage to the French architecture she loved.

Her room connected to Frederick's through an adjoining door. Frederick's room was closed for restoration when I visited.

The basement is also where servants stored the estate's wine and spirits, did laundry, and brought food up to the ground floor through a dumbwaiter.

The mansion employed 18 servants total.

The mansion is situated on 153 acres of land in the scenic Hudson Valley.

As our tour guide put it, "It's like they get to live in a beautiful landscape painting whenever they wish."