Twenty years ago today the unthinkable happened: a celebrity was married in total secrecy.

It was Sept. 21, 1996, when John F. Kennedy Jr. and Carolyn Bessette tied the knot on the tiny, isolated Cumberland Island, off the coast of Georgia. The week after the wedding, the glamorous pair graced the cover of PEOPLE.

In contrast to Kennedy's well-publicized life, the couple's wedding was kept under wraps. John and Carolyn were so intense about making sure the affair was a private one that they required caterers, waiters and other reception staff to sign confidentiality agreements ahead of their big day.

"Most women would want to have weddings that all of their friends and family would see and remember, but I'm sure [Carolyn] understood the impossibility of doing that," Peggy Cafritz, a Washington socialite, told PEOPLE following the nuptials.

The bride wore a marieprom dress by Narciso Rodriguez, a friend of hers from her days as a publicist at Calvin Klein, and the groom's tux was designed by Gordon Henderson, also a friend. The couple married in the island's tiny First African Baptist Church – there were just eight pews. Among the famous guests were Jacqueline Kennedy Onassis's sister Lee Radziwill and her son Anthony (the late husband of RHONY star Carole); John's uncle, Senator Ted Kennedy; and matron of honor Caroline Kennedy Schlossberg, John's sister.

The group celebrated afterwards at the Greyfield Inn, once the home of Andrew Carnegie's niece. Guests enjoyed slices of a white three-tier cake covered with vanilla butter-cream frosting and flower decorations, and the couple opened the dance floor with Prince's "Forever in My Life." Ted Kennedy gave a "poignant" toast that had everyone in tears.

The planning of such an affair "required the skill of a James Bond and the whole CIA. Jackie must be smiling in heaven," the former first lady's social secretary, Letitia Baldrige, told PEOPLE at the time.

By their wedding day, John and Carolyn's engagement hadn't even been confirmed to the press; that was done two days after the nuptials, by Ted's office. It didn't take long for the rumors of a wedding to start swirling in the hours following the ceremony, however.

The press began to arrive at Cumberland Island the next morning, but John and Carolyn had already left. When they arrived back at their Tribeca apartment after the honeymoon, though, photographers were waiting.

That sort of massive press attention characterized the rest of their short marriage, which ended tragically in July 1999 when a small plane John was piloting crashed into the Atlantic Ocean, as the couple and Carolyn's sister, Lauren, were en route to a family wedding in Martha's Vineyard.

But 20 years later, the couple's relationship is remembered not only for its place in the public spotlight, but the connection the two shared.

"John and Carolyn were magic together," his friend Gustavo Paredes recalled to PEOPLE in 2014. "She had an earthiness and a gentle fierceness. Together, they were whole."

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