I'm sure you've all heard of the uber-top-secret-this-message-will-self-destruct Skull and Bones society at Yale. The Bushes have been members since way back when; other Bonesmen include an illustrious list of other presidents (William Howard Taft), high-up business executives, Supreme Court justices, politicians and journalists. We know that their headquarters is called "The Tomb" and it houses many secrets, but a few of those have been uncovered thanks to the intrepid journalism of Alexandra Robbins, who managed to get more than 100 Bonesmen to speak to her about the Stonecutters, errr, Skull and Bones. Here are 10 of the things that may (or may not) lie within the walls of The Tomb.

geronimo1. Geronimo's skull. This one is pretty well-known, and although it's never been proven, Robbins says it's one of the more likely items to be behind the closed doors. And who allegedly stole it? None other than Prescott Bush, G.W.'s grandpa. Six members of Skull and Bones, including Bush, were tasked with guarding Fort Sill, the site of Geronimo's grave, during WWI. Various documents have been found verifying that the skull does indeed reside with the Skull and Bones Society, but some experts say there's no way Geronimo's cranium is anywhere but his final resting place at Fort Sill.

2. Pancho Villa's skull. The rumor is that the society bought the skull for $25,000 in 1926, shortly after the skull was stolen from Villa's grave. Skull and Bones has denied this, of course, and some members have gone off the record saying that the society is way too cheap to pay that kind of money for a skull. Robbins originally confirmed in her book that Skull and Bones was definitely in possession of Villa's cabeza, but has since retracted that. Hmm.

3. Martin Van Buren's skull.

With so many U.S. presidents in their ranks, I guess it makes sense that the Bones would have a presidential skull hidden away somewhere. This one has never been even remotely proved and for all we know, all parts of Van Buren are still safely buried in the Kinderhook Cemetery in Kinderhook, N.Y. But why Van Buren? Your guess is as good as mine"¦ one thing's for sure, though: the Van Buren Boys certainly aren't going to be happy about this. And they're every bit as mean as he was, you know.

4. A set of Hitler's silverware. Another "why?" item, in my opinion. This isn't nearly as special as you might think, though: just head to Alabama to see some Fuhrer relics. His tea service resides in Anniston, Alabama, and his typewriter has a home in Bessemer. His Rolls Royce is in Cochise, Arizona; his hat and coat are in Atlanta; some of his beer steins are in Lomita, California; his desk keys are in Estes Park, Colorado; and his supposed horse is buried in St. Rose, Louisiana. So keep your silverware, Skull and Bones. We're not impressed.

skull5. Coffins, which seems appropriate for a place called "The Tomb." Legend has it that initiates have to lie in the coffins and recount all of their sexual experiences and fantasies to the patriarchs (everyone who isn't an initiate). Some reports have debunked this, though, saying that no coffins are involved "“ the initiates merely have to stand in front of a portrait of a woman named Connubial Bliss and recite their entire sexual history.
6. License plates bearing the number 322. According to an account of a girl whose Bonesman boyfriend took her in to tour the Tomb, a whole wall is filled with license plates with the number "322." This is the number that represents the group, although the reason why is another one of those mysteries that outsiders have been guessing at for years. Apparently Bonesmen are told to "liberate" any license plate with their number on it, so if you happen to have a license plate with that particular combination, don't be surprised if it goes missing.

7. The gravestone of Yale's founder. Robbins says the original gravestone of Elihu Yale was stolen from its original spot on the grounds of St. Giles' Church in Wrexham, Wales, and is now sitting in a glass case in the Tomb.

8. Large portraits of its most famous members, including William Howard Taft and George H.W. Bush. A conservator in Connecticut spent six years restoring 15 paintings from the Skull and Bones headquarters and says the inside isn't all that foreboding. She likened it to the Addams Family "“ kind of "funny-spooky."

9. A couch. Yep. Crazy, huh? Despite the presence of skulls and gravestones and coffins, one member said the Tomb was a lot like a college dorm, just swathed in more secrecy. He told Robbins it was "A place that used to be really nice but felt kind of beat up, lived in. There were socks underneath the couch, old half-deflated soccer balls lying around."

10. "Madame Pompadour," a skeleton which Bonesmen believe to be Madame de Pompadour. She resides in the Inner Temple and protects founding papers and other important society documents.