<p class="ingestion featured-caption">Hillwood Estate.Talia Lakritz/Business Insider</p><ul class="summary-list"><li>Hillwood Estate was the home of breakfast-cereal heiress Marjorie Merriweather Post.</li><li>She collected art from 18th-century France and imperial Russia for display in her 36-room mansion.</li></ul><p>Marjorie Merriweather Post was once known as America's richest woman, with an estimated net worth of $250 million — around $1.8 billion today when adjusted for inflation.</p><p>She inherited her father's <a target="_blank" class href="https://www.businessinsider.com/create-eat-cereals-post-heres-what-its-like-2023-5">Post cereal</a> fortune in 1914, but Post helped build the company into the General Foods Corporation by acquiring brands like Jell-O and Maxwell House. She also served on its board of directors.</p><p>With her success as a businesswoman, socialite, and philanthropist, Post built homes to match her elite status.</p><p>In 1955, she purchased Hillwood Estate in Washington, DC, and renovated it into a 36-room, 26,000-square-foot mansion with a focus on entertaining and displaying her priceless art collections.</p><p>Post only lived at Hillwood during fall and spring. She spent winters at her <a target="_blank" class href="https://www.businessinsider.com/inside-trump-mar-a-lago-club-photos-2018-1">Mar-a-Lago</a> estate in Palm Beach, Florida, which is now owned by former President <a target="_blank" class href="https://www.businessinsider.com/what-its-like-to-go-inside-mar-a-lago-2022-8">Donald Trump</a>, and summers at Camp Topridge in New York's Adirondack Mountains.</p><p>Access to Mar-a-Lago remains limited due to Trump's residence there, but Hillwood is a museum open to the public.</p><p>Take a look inside Post's opulent home and its surrounding gardens.</p>