For the next quarter century, visitors at Brooklyn's Green-Wood Cemetery will be able to bury a bit of themselves—a personal secret, written on a plain white index card and left behind for dead. These acts of confessional death are made possible by French artist Sophie Calle's Secret, a new installation (commissioned by Creative Time) that's reverent, discomforting, and brilliant.

Secret places a 500 pound marble obelisk atop a hill at Green-Wood. Bearing the epitaph "HERE LIE THE SECRETS OF THE VISITORS OF GREEN-WOOD CEMETERY," it stands above a subterranean chamber and opens at a narrow slit. Calle's work encourages visitors to write down a personal secret and cast it away into the obelisk, where it will sit underground for days, weeks, or even years—inaccessible to all but Clalle herself, who will return to the obelisk in order to burn the collected secrets when the chamber fills.

Last Saturday afternoon during Secret's opening, visitors leisurely strolled around the grassy hill it's set upon, pausing to jot down their secrets before sliding them into obelisk. It took only a few hours for the piece's underground chamber to become completely full of secrets, forcing Calle's on-site staff to bring out a small glass faux-casket, where late-day visitors piled on more secrets. Those minding the box assured visitors that their secrets, too, would be kept private and, eventually, incinerated.

Calle herself was present at Green-Wood over the weekend, attending to a line of very committed visitors who wished to confide their secrets to her in person. During these anonymous conversations, Calle wrote down each secret and, after promising to never tell a soul, sealed each in an envelope that was also destined to die in flame. As Calle gave each of her secret-givers ample time to divulge, the line for one-on-ones with her quickly got out of hand. Wait times at 4 p.m. Saturday were 45 minutes or more.

(Courtesy of Sophie Calle / Creative Time)

Bed-Stuy resident Corina Copp was undeterred by the hour wait to visit with Calle. "I just wanted to look into her eyes while I told [my secret]. It felt different than what I'd expected. It was so much more emotional." Copp described Calle's candor as open, curious, and invested, and said she would gladly share another personal secret aloud with the artist.

"Now I feel like I could tell her anything."

As a work of art, Secret serves as a perfectly unassuming addition to the Green-Wood's beautiful sweeping hills and stately tombs. It demands quietude, self-reflection, and an act of letting go. It's not hard to imagine some visitors returning to Calle's obelisk again and again during its 25 year stay, recalling past secrets they've given up to the aether and slipping in new confessions.

"This is my first time even being aware of Calle's art. I like it here in the cemetery, there's aspects of the eternal, and also the fleeting, at the same time. I think it's a great conceit for an exhibit," Jonah Allon, 22, said shortly after adding his own secret to the cache. "Nothing came to mind, immediately, when I thought of my secret, but I spent some time on the hillside taking in the scene. I didn't want to rush it or put anything to paper before I had a good idea of what I wanted. But once it did, it just flowed right out of me. When I did decide, it felt very natural and cathartic."

When asked why he chose not to share his secret out loud with Calle herself, Allon stressed it wasn't the long wait time that stopped him. "It's a secret for a reason," he replied. "I've chosen not to divulge it to a lot of people because it's something that's deeply personal to me. The thought of telling it to some one anonymously, while on some level comforting, still turns me off a bit. If I'm going to tell a secret, it's going to be just the one—I don't want to be promiscuous with my secrets."

Green-Wood Cemetery is located at 500 25th Street in Brooklyn. The installation will be there for the next 25 years.