Post poured her Post Cereals inheritance into every detail. The architecture is a Mediterranean-style villa, an adaptation of Hispano-Moresque design popular in Palm Beach at the time. A two-story central block houses the main living quarters, while lower subsidiary wings separate family life from entertaining space -- a deliberate choice by Post to keep the massive estate from feeling overwhelming. Joseph Urban's interior work brought a theatrical flair to the rooms, filling them with ornamental tiles, tapestries, and artwork that would later be appraised at $8 million on their own. Post hosted social events at the estate beginning in 1948, and since 1957 Mar-a-Lago has traditionally hosted the International Red Cross Ball, an annual white-tie affair she founded. The Department of the Interior would later note that the property provided "an excellent picture of winter resort life in Palm Beach prior to the Depression."

Post dreamed of Mar-a-Lago serving as a Winter White House for visiting presidents. She donated the estate to the federal government upon her death, but Richard Nixon preferred Key Biscayne and Jimmy Carter was not interested. Maintenance costs overwhelmed the allocated funds, and Congress returned the property to the Post Foundation in 1981. Listed for $20 million, it attracted so little interest that demolition was approved. Then Donald Trump entered the picture with a $15 million offer, which was rejected. His countermove was audacious: he purchased the strip of land between Mar-a-Lago and the ocean for $2 million, threatening to build a home that would block the estate's beach view. Competing interest collapsed, and Trump acquired Mar-a-Lago in 1985 for $7 million -- a combined cost of roughly $10 million, half the asking price.

Facing financial difficulties in the early 1990s, Trump attempted to subdivide the property. Palm Beach rejected that plan, so he converted the estate into a members-only club in 1995. The initiation fee started at $200,000, dipped to $100,000 after the Madoff scandal thinned the wallets of Palm Beach's elite, then climbed steadily -- reaching $1 million by 2024, with annual dues of $20,000. The club hosted concerts by Celine Dion and Billy Joel, celebrity guests including Michael Jackson and Lisa Marie Presley for their 1994 honeymoon, and the enduring International Red Cross Ball. By 2017, membership neared its 500-person cap. Trump married Melania Knauss at the estate in 2005, with Bill and Hillary Clinton among the guests -- a bipartisan gathering that seems almost unimaginable in retrospect.

During his first presidency, Trump called Mar-a-Lago his "Winter White House," a label with historical irony given Post's original dream. A Sensitive Compartmented Information Facility was installed for secure communications with the Pentagon and White House Situation Room. In February 2017, Trump hosted Japanese Prime Minister Shinzo Abe at the club -- the first use of the estate for international diplomacy. When North Korea launched a missile that same weekend, Trump and Abe conferred in full view of the other club members dining nearby. In April 2017, Chinese President Xi Jinping visited, and it was at Mar-a-Lago that the decision was made to strike a Syrian airfield. Presidential visits triggered temporary flight restrictions affecting operations within a 30-nautical-mile radius, shutting down nearby Palm Beach County Park Airport for consecutive weekends.

Mar-a-Lago has accumulated layers of consequence that Post could never have imagined. After leaving office in January 2021, Trump transported presidential records to the estate, leading to a 2022 FBI search and a federal investigation into mishandling of classified documents. The property's valuation became central to a New York civil fraud case: Palm Beach County assessed Mar-a-Lago between $18 million and $27.6 million based on club operating income, while Trump's financial statements listed figures as high as $627 million. Forbes estimated the actual value at around $350 million in 2022. Through it all, the estate endures -- the Spanish tiles, the tower with its panoramic view of Palm Beach, the grounds stretching from sea to lake just as Marjorie Merriweather Post designed them nearly a century ago.