Hillwood's interiors and gardens first opened to the public in 1977, then reopened in 2000 after extensive renovations.

One adult ticket can be purchased with a $17 suggested donation on weekdays and $20 on weekends through Hillwood's official website.

Hillwood offers self-guided tours through its Hillwood app, as well as guided tours throughout the day.

Post's father, CW Post, founded the Postum Cereal Company in 1895. When he died in 1914, Post, at 27, took ownership of the $20 million company. She helped grow the cereal company into the General Foods Corporation and served on its board for over 20 years, becoming one of the first women in America to serve on a corporate board of directors.

Post was married and divorced four times and had three children: Dina Merrill, Eleanor Post Hutton, and Adelaide Breevort Close. She bought Hillwood after divorcing her third husband, Joseph Edward Davies.

Portraits of the Romanovs, the Russian dynasty that ruled from 1613 to 1917, hung above the grand staircase, and a marble bust depicted the Duchesse de Châteauroux, one of King Louis XV's mistresses.

Post intended for Hillwood to become a museum open to the public, and had display cases built in almost every room on the first floor.

The room's gilded wood paneling and fireplace mantle came from King Louis XVI-era homes in Paris.

Post used the French Drawing Room as a reception area to greet guests as they arrived for her dinners and garden parties.

The Pavilion was equipped with a projector and sound system for movie screenings, and the walls were covered in velvet for better acoustics.

Staff members served drinks in a wet bar located just outside the Pavilion.

Painted in 1883, "A Boyar Wedding Feast" is one of the most famous Russian paintings in existence. It depicts a wedding between two noble Russian families as it would have looked in the 16th and 17th centuries.

Post called the Icon Room her "treasury."

Both eggs were gifts from Tsar Nicholas II to his mother, Maria Feodorovna.

The Yusupov princes gifted the music box to their parents for their 25th anniversary. The building shown on the front is Moika Palace, best known as the site where Gregori Rasputin was killed in 1916.

Post used the Library as a smaller gathering space with friends or to read and relax on her own. A portrait of her father, CW Post, hung above the fireplace.

The oak paneling on the walls in the Dining Room came from an 18th-century home in Paris, and the walls featured Dutch paintings of hunting scenes.

The table could seat over 30 people. A leaf from the table was displayed separately to allow visitors to get a closer look.

The porcelain dishware was originally made in France for European aristocrats in the 1740s and later collected by wealthy art enthusiasts such as Post and the Rothschilds.

While the enclave is called the Breakfast Room, Post usually ate lunch and dinner there.

The kitchen didn't have a dishwasher because all of Post's dishes had to be washed by hand.

The butler's pantry also featured a dumbwaiter for transporting Post's porcelain and glass dishware to and from storage in the basement.

Jell-O, a General Foods brand, made appearances at Post's dinner parties in the form of aspic rings and gelatinous salads, a popular food trend in the 1950s.

The Vanderbilt family's 54-room mansion in Hyde Park, New York, also featured a grand staircase with a velvet-covered railing.

True to its name, the Snooze Room included a daybed for midday naps.

The English Bedroom, named for its 19th-century English furniture set, served as a guest room when Post's daughters visited Hillwood.

The Adam style, popular in the late 18th and early 19th centuries, was coined by Robert and James Adam, who were architects and designers from Scotland.

The Adam Bedroom Suite also functioned as a guest bedroom.

The second-floor library housed a television, a touch of modernity amid the English country house aesthetic.

A display case held around 50 items made from bloodstone, Post's birthstone.

"She took her various board duties seriously, and she planned her schedule, whenever possible, around those duties," Post's financial secretary, Betty Canella, said of her boss according to the audio tour.

Call buttons by the bathtub allowed Post to summon a maid, social secretary, or seamstress.

This platinum and diamond necklace was designed by jeweler Harry Winston.

Diamond engagement rings were a relatively new phenomenon at the time — the De Beers advertising campaign that popularized diamonds in connection with engagements and weddings ran in the 1940s.

Post and May were married for six years, divorcing in 1964.

Among the gallery's many artifacts was the Buch Chalice commissioned by Catherine the Great in 1790. The gold goblet, used in religious rituals, featured 5,492 diamonds totaling 152.11 carats, according to Hillwood's official website.

The Hillwood app featured a separate self-guided tour just for the gardens.

The French Drawing Room inside led out into this garden, with the English ivy walls making it feel like another room. Paths of water called rills divided the space and led to a statue of Diana, the goddess of the hunt, on the other side.

The Lunar Lawn, named for its half-moon shape, was dotted with elms, false cypresses, and various flowers.

Visitors could step across the pool of water on a path of millstones.

The Greenhouse allowed Post to enjoy fresh flowers at Hillwood year-round. She even had fresh flowers shipped from Hillwood to Mar-a-Lago and Camp Topridge.

In addition to the Greenhouse, Hillwood also had a cutting garden that supplied seasonal floral arrangements.

Every year, on her birthday and death anniversary, Hillwood puts a bouquet of fresh flowers on the memorial in the Rose Garden. I visited on September 13, which happened to be the day after her death anniversary, so the flowers on the monument still appeared fresh.

It's not often that one gets to look inside the home of a modern businesswoman who was one America's wealthiest figures, but Post always intended for Hillwood to welcome members of the public.

She often hosted school groups and educational events during her lifetime to allow people to view her art collections, and her legacy continues today through the museum and gardens at Hillwood Estate.