Everybody loves speculating about the secret societies that may — or may not — control the world. Their rituals and their inner workings sound so ominous. But did you know that an estimated 20 of our presidents have aligned themselves with secret societies over the years? Fortunately, most of these secret societies function more like social clubs than cults.

Read on to discover the most interesting — and exclusive — secret societies that U.S. presidents have joined. And on page 14, find out whether President Donald Trump has joined any secret societies.

1. Freemasons

• Presidents who joined: George Washington, James Monroe, Andrew Jackson, James Polk, James Buchanan, Andrew Johnson, James Garfield, William McKinley, Theodore Roosevelt, William Howard Taft, Warren Harding, Franklin Roosevelt, Harry Truman, Lyndon Johnson, and Gerald Ford

History reports that Freemasonry, one of the most famous secret societies, “evolved from the practices and rituals of the stonemasons’ guilds in the Middle Ages.” The first American lodge was established in Philadelphia in 1730. George Washington joined the Masons, and ascended through the ranks. He even became the first Worshipful Master of Alexandria Lodge No. 22.

As president, Washington approved the use of Masonic symbols in the Great Seal of the United States. (You can still see them on the one-dollar bill!) The All-Seeing Eye above an unfinished pyramid looks “unmistakably Masonic,” History reports. And the scroll beneath proclaims the advent of a “New Secular Order.” That’s one of Freemasonry’s longstanding goals.

Next: This secret society branched off of Freemasonry.

2. Rosicrucians

• Presidents said to have joined: George Washington and Abraham Lincoln

Another name you’ll sometimes hear in connection with the Freemasons? Rosicrucians. Haverford College professor Darin Hayton reports that “Rosicrucians burst onto the scene in the early 17th century with a couple manifestos laying out the tenets of this secretive brotherhood.” The cultural movement believed in the existence of an esoteric world order. And they supposedly used occult practices at the time.

As various groups carried on the tradition, Philadelphia hosted a long line of Rosicrucian activities. That included the formation The Franternitas Rosæ Crucis. The group says that George Washington, Benjamin Franklin, and Abraham Lincoln joined. Plenty people like to speculate that iconic presidents really did participate, but we have little evidence.

Next: Only one president joined this secret society.

3. F.H.C.

• Presidents who joined: Thomas Jefferson

Thomas Jefferson probably didn’t join the Freemasons. But “he did claim membership in another secret society – the F.H.C (also known as the Flat Hat Club),” according to Monticello. The club began in the 1750s at the College of William and Mary. It represents the first college fraternity in America. But the Flat Hat Club’s activities lapsed during the Revolutionary War. Afterward, they were never revived. So relatively little information remains about the club.

Yet we do know that Thomas Jefferson became a member when he attended the college in the 1760s. In a letter, Jefferson confirmed his membership. But he also claimed that the Flat Hat Club had “no useful object,” an opinion he also seemed to have about other fraternal organizations and secret societies.

Next: Many presidents joined this strange organization.

4. Independent Order of Odd Fellows

• Presidents who joined: Ulysses S. Grant, Rutherford B. Hayes, William McKinley, Warren G. Harding, Franklin D. Roosevelt, and Harry S. Truman

Several presidents reportedly joined the Independent Order of Odd Fellows. This group has more skeletons in its closet than other secret societies — at least literal skeletons. The Los Angeles Times reports that the Odd Fellows “dates to 17th-century England as a charitable organization that worked to help families in need and buried their dead. But today, the Odd Fellows occasionally makes the news for lodges where skeletons have been discovered in closets, drawers, attics, and crawl spaces.

The first American Odd Fellows lodge opened in Baltimore in 1819. The Times reports that the organization’s symbol — three interlocking rings — represents friendship, love, and truth. And as for those skeletons? The Times reports that they played a role in initiation rites. And they “likely were purchased from scientific or fraternal supply companies.”

Next: This secret society has a bizarre name, but a relatively mundane purpose.

5. Concatenated Order of Hoo-Hoo

• Presidents who joined: Theodore Roosevelt and Warren G. Harding

According to the Forest History Society, the Concatenated Order of Hoo-Hoo began in Arkansas in 1892 to promote unity and fellowship among men in the lumber industry. This society eventually grew into an international group. U.S. presidents Theodore Roosevelt and Warren G. Harding reportedly numbered among its members (PDF).

Unlike many other secret societies, the Concatenated Order of Hoo-Hoo wanted their organization to feel “unconventional and unregimented.” They chose officer titles that reflected that spirit, drawing inspiration from a Lewis Carroll book. They called the chief executive officer the Snark of the Universe. That officer led a team of a Supreme Hoo-Hoo, a Scrivenoter, Bojum, and Jabborwock. As its mascot, the group chose a black cat with its tail forming the number nine.

Next: This group numbers among the most famous secret societies. 

6. Skull and Bones

• Presidents who joined: William Howard Taft, George H.W. Bush, and George W. Bush

In 1832, students at Yale University founded one of the most famous secret societies: Skull and Bones. Business Insider reports that “Since then, the group has come to signify all that both mesmerizes and repulses the public about the elite.” Each year, only 15 juniors get chosen for membership in the club. New members divulge personal details and agree to leave part of their estates to the club. But in return, they receive a promise of lifelong financial stability.

Several members of Skull and Bones went on to become president of the United States. The first was William Howard Taft. The next “Bonesman” in the Oval Office was George H.W. Bush. Bush men have been Bonesmen for generations, according to The Atlantic. And George W. Bush goes down in history as the third Bonesman to become president.

Next: Even John F. Kennedy may have joined this group.

7. Order of the Elks

• Presidents who joined: Warren G. Harding, Franklin D. Roosevelt, Harry S. Truman, John F. Kennedy

Most people have heard of the Elks. But that doesn’t diminish the group’s appeal as one of the secret societies that presidents have decided to join. As one researcher tells The Atlantic, many service-oriented organizations, including the Elks, actually “have a great deal of secret ritual” within their structure.

Many of these organizations, like the Freemasons, require new members to swear an oath of allegiance. If they won’t swear the oath, they can’t become a member. The group reportedly began in 1867 (PDF). It counted presidents such as Warren G. Harding, Franklin D. Roosevelt, Harry S. Truman, and even John F. Kennedy as members.

Next: Only one president joined this organization.

8. The Order of the Red Friars

• Presidents who joined: Richard Nixon

One of the lesser-known secret societies, the Order of the Red Friars got its start in 1913 at Trinity College, now Duke University. Duke has seen five known secret societies. But as Leah Abrams reports for The Chronicle at Duke, “The men chosen for the Order of the Red Friars were meant to be the best and brightest men of their year, holding positions in the Chronicle, IFC, and Student Government; in special cases, even outstanding graduate students were tapped.”

Members of the society, including Richard Nixon, were chosen in groups of seven each year. They had access to the Board of Trustees, key university administrators, and prominent Duke alumni in the professional world. Members of the Order of the Red Friars helped shape university policy. They also influenced student life at Duke. The group voluntarily disbanded in 1971. And we know relatively little about what Nixon and others did as part of the group.

Next: Many Republican presidents have supposedly joined this secret society.

9. Bohemian Club

• Presidents who joined: Theodore Roosevelt, Calvin Coolidge, Herbert Hoover,Dwight D. Eisenhower, Gerald Ford, Ronald Reagan, and George H.W. Bush

The Washington Post characterizes Bohemian Grove, the California meeting place of the Bohemian Club, as a place “where the rich and powerful go to misbehave.” Vanity Fair reported in 2009 that the Bohemian Club has included “every Republican president since Coolidge.” It also adds that “conspiracy theorists believe the Bohemian Grove’s idyllic grounds, in northern California, are host to right-wing, old-boy machinations about the New World Order.”

To join the club, you have to be invited by several members. You also have to pay a $25,000 initiation fee. A University of California professor characterizes Bohemian Grove as “an Elks Club for the rich; a fraternity party in the woods; a boy scout camp for old guys, complete with an initiation ceremony and a totem animal, the owl.”  The Bohemian Club reportedly began in 1872 in San Francisco. And members began going on their retreat shortly after the club’s founding.

Next: Another secret society came out of the Bohemian Club.

10. The Family

• Presidents who joined: Herbert Hoover

Thrillist reports that another secret society came about as an offshoot of the Bohemian Club. Called The Family, this private club supposedly began in 1901. Its founders were newspapermen who decided to leave the Bohemian Club. Just like the Bohemian Club, The Family has successfully kept most of the details of its activities under wraps.

Yet a few details have surfaced. This secret society supposedly calls its new members “Babies,” its standard members “Children,” and the club president “Father.” The club also reportedly forbids that any of the members use its services or facilities for business. And the group continues to maintain a clubhouse in San Francisco, as well as a property 35 miles away in Woodside.

Next: This group numbers among the secret societies joined by several recent presidents.

11. Trilateral Commission

• Presidents who joined: Jimmy Carter, George H.W. Bush, and George W. Bush

It’s not quite as ominous-sounding as some other secret societies. But Thrillist reports that an organization called the Trilateral Commission can count a few presidents among its members. David Rockefeller founded the group in 1973 to encourage cooperation among countries around the world.

The members of the Trilateral Commission meet biannually “to tackle the major issues facing the planet and decide how best to approach them.” Of course, the group has attracted its fair share of criticism. And some conspiracy theorists even believe that this group was behind 9/11 — a surprisingly common allegation against various secret societies.

Next: Conspiracy theorists think this group has a nefarious mission.

12. Bilderberg Group

• Presidents who joined: Gerald Ford and Bill Clinton

Thrillist reports that an organization called the Bilderberg Group also numbers among the secret societies with presidents as members. “Since 1954, influential people involved in world affairs have met secretly to discuss how to foster better cooperation between countries on a range of issues,” Thrillist explains. Time reports that little is known about the groups’s annual gatherings. But that doesn’t stop conspiracy theorists from going wild.

Time notes that in 2000, longtime member Denis Healey alarmed those conspiracy theorists by saying, “To say we were striving for a one-world government is exaggerated, but not wholly unfair. Those of us in Bilderberg felt we couldn’t go on forever fighting one another for nothing and killing people and rendering millions homeless. So we felt that a single community throughout the world would be a good thing.”

Next: What do we know about Barack Obama’s membership in secret societies?

Has Barack Obama joined any secret societies?

Many Americans wonder whether Barack Obama has joined any secret societies. There’s little evidence of his participation in groups like the Bohemian Club, Skull and Bones, or the Bilderberg Group. And he doesn’t appear to have joined Prince Hall Masonry, which Salon notes is a traditionally African-American Masonic organization.

Nonetheless, people love conspiracy theories. And many people have theorized that Obama must belong to the Illuminati, a group that Salon notes has “not existed for more than two centuries.” In the 18th century, the group advocated for “then-radical ideals such as separation of church and state, free assembly, and democratic elections.” But there’s little evidence that the Illuminati is still around — or that Obama is a member.

Next: Find out whether Donald Trump has joined any secret societies.

Does Donald Trump belong to any secret societies?

Similarly, we have little evidence that Donald Trump has joined any secret societies. Yet that doesn’t stop conspiracy theorists from looking for connections. Conspiracy theorists have alleged that Donald Trump is aligned with the Illuminati. They think that Trump is working toward a clandestine world government called the New World Order. The theories just get harder to believe from there.

As The Huffington Post notes, the Illuminati originally branched off from the Freemasons. But the group has since “become a prime focus for conspiracy theorists, many of whom credit Illuminati agendas for every conceivable disaster, mystery, and economic downturn.” Of course, we have little evidence that the Illuminati still exist. And we have even less evidence that Donald Trump is a member. But there’s one relatively secret group that we do know he’s going to join.

Next: Donald Trump and Barack Obama are both members of this club.

Both Donald Trump and Barack Obama belong to The Presidents Club

Donald Trump and Barack Obama don’t seem to have anything in common, much less membership in one or more secret societies. But both number among the elite ranks of men who have served as president. Time reports that both will belong to a club created by Herbert Hoover and Harry S. Truman for former presidents. As the publication explained, “the Presidents club became an actual fraternity, an abiding alliance between sitting and former Presidents born of the experiences they had shared, the mistakes they avoided and the opportunities they seized. ”

Former presidents, including Barack Obama and eventually Donald Trump , also have access to a literal clubhouse. Time reports that the so-called Presidents club calls home “a building the government acquired in the late 1950s, which Richard Nixon reassigned in 1969 for the sole use of former Presidents when they came to town.”

Read more: It’s Not Just Donald Trump: Here’s Why Presidents Are Also Celebrities

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