A shadowy and controversial secret club meets in the California woods every year - and at least 5 US presidents were members

The traditions go back to the earliest days of the private gentleman's club, which sprang up in 1872 in San Francisco. The Bohemian Club began renting the campground for an annual retreat, before purchasing it outright in 1899.

"You come upon it suddenly," poet and club member Will Irwin wrote of the Grove in 1908. "One step and its glory is over you."

Originally a cluster of newspaper writers who'd adopted a "bohemian lifestyle," the club expanded overtime to include artists, businessmen, military leaders, and politicians.

While the club has diversified in terms of its members' professions, women have been barred from joining since its inception. A 1978 lawsuit did result in the Bohemian Club being required to hire female employees, however.

So how do you land a coveted spot in the approximately 2,500-member club? Vanity Fair reported that you either need to snag invitations from several members, or languish for decades on the club's waiting list. You've also got to be prepared to drop $25,000 on your initiation fee.

G. William Domhoff, a University of California, Santa Cruz professor emeritus of psychology and sociology, has studied the Bohemian Club extensively. In a post on the site Who Rules America? he described the Grove as "... a place where the powerful relax, enjoy each other's company, and get to know some of the artists, entertainers, and professors who are included to give the occasion a thin veneer of cultural and intellectual pretension."

The motto of the Bohemian Club is "weaving spiders, come not here." It's a line from William Shakespeare's "A Midsummer Night's Dream," reflecting the idea is that members are not supposed to worry about work or business deals while at the club.

Because of its secrecy, strange ceremonies, and elite body of members, the Bohemian Club has long been the subject of sinister online rumors. Right-wing conspiracy theorist Alex Jones even attempted to film a cremation ceremony there in 2000.

The Bohemian Grove has also attracted a number of protestors who aren't concerned with the allegedly occult aspects of the proceedings.

"The thing we should be concerned about is the lakeside talks," activist Mary Moore told Vice in 2011. " They are public policy talks, where these powerful people discuss and choose policy, but they do so in secrecy, with no public scrutiny."

A number of journalists have managed to infiltrate the campground — with mixed success. Alex Shoumatoff investigated reports the Club was illegally logging for Vanity Fair, and was caught and detained for trespassing. Philip Weiss snuck into the Bohemian Grove in 1987 and spent a few days mingling with the rich and powerful as they attended speeches, boozed it up from breakfast to nightfall, and urinated on trees. He wrote about the strange experience for Spy magazine.

On Gawker, Sophie Weiner also described her own stint working as a dining server at the Grove in 2016. She described the retreat as a place where the elite could "engage in behavior that doesn’t usually fly for people of their stature in the regular world."

While many politicians have attended Bohemian Grove functions, the number of presidents who were actually club members is seemingly greatly overstated. Calvin Coolidge and Gerald Ford, for example, are often erroneously cited as members.

Domhoff concluded that the Bohemian Club reveals that there is a "socially cohesive upper class" in the US, but the Grove activities are "harmless."

"The Grove encampment is a bunch of guys kidding around, drinking with their buddies, and trying to relive their youth, and often acting very silly," he wrote.

Theodore Roosevelt was granted honorary club membership when he became president.

In a brief 1903 letter to Bohemian Club member Edgar D. Peixott, he expressed gratitude for the "honor conferred upon me." He also offered his regrets that he could not make it to a club function.

Hoover joined the Bohemian Club in 1913. By that point, he had amassed a fortune of $4 million in the mining and engineering industry.

Hoover and a group of fellow Stanford alumni ultimately founded their own camp in the Bohemian Grove: the Cave Man Camp. An abandoned statue of a caveman that had been previously used in a club production inspired the name, according to the book "Hoover, the Fishing President: Portrait of the Private Man and His Life Outdoors."

In "Ike and Dick: Portrait of a Strange Political Marriage," Jeffrey Frank writes Hoover always "treasured his membership" and was avid about scouting out new club recruits. In 1950, he invited then-congressman Richard Nixon on a trip to the Bohemian Grove.

During his meet up with Hoover at the Bohemian Grove in 1950, Nixon happened to bump into his future running mate, according to "Ike and Dick: Portrait of a Strange Political Marriage."

General Dwight D. Eisenhower was also there, meeting with the Cave Man Camp. Two years later, the pair would make up the Republican presidential ticket in 1952.

He would also go on to join the Cave Man Camp after becoming a member in 1953. Domhoff characterized the camp as "highly conservative," even for the Bohemian Club.

Nixon would also, reportedly, use his position in the Bohemian Club to launch his ultimately successful run for the White House.

According to the book "Kennedy, Johnson, and the Nonaligned World," Nixon delivered a Lakeside Speech to his fellow club members in July 1967. He outlined his ideas on American foreign policy, in what he called the "first milestone on my road to the presidency." Domhoff wrote that Nixon also got verbal confirmation from club guest Ronald Reagan that he would not challenge him in the Republican primary that year.

According to Domhoff, Nixon was "so full of himself over the Bohemian Grove" that he wanted to give the lakeside talk in 1971. The idea of a sitting US president giving an off-the-record speech before a cluster of some of the most powerful people in the country sparked controversy in the press. The club leaders asked him to back out, and Nixon acquiesced.

But the Watergate tapes indicated that Nixon may have had mixed feelings about the Bohemian Club. He was recorded describing the Bohemian Grove activities using derogatory slurs.

Ronald Reagan was officially inducted into the Bohemian Club in 1975, the year before he tossed his hat into the 1976 presidential campaign.

He belonged to the Owl's Nest Camp, which he shared with execs from United Airlines and a number of other companies that were powerful in the 1970s.

During the 1980 presidential election, Reagan avoided the Bohemian Grove because he "discovered I might be an embarrassment to our fellow Bohemians because of the round-the-clock surveillance by the press. They camp down at my driveway these days," according to "Reagan: A Life in Letters."

In his Spy magazine expose, Weiss reported that he was able to meet with Reagan in the Owl's Nest Camp. They made some small talk, and Reagan off-handedly confirmed that he had assured Nixon he "wouldn't challenge him outright for the Republican nomination in 1968."

Weiss wrote that Reagan gave the lakeside talk that year and took questions from club members afterwards, during which he called for four year terms for congress members and greater regulation of the press.

George H.W. Bush joined the club in 1973, while chairing the Republican National Committee during the Watergate scandal.

Domhoff writes that Bush belonged to a camp called Hill Billies, along with top executives from Bank of America, General Motors, and Procter & Gamble.

Bush also brought along a future president as a guest on one trip to Bohemian Grove. He introduced his son — George W. Bush — at a lakeside talk in 1995, saying that he'd make a great president, according to Domhoff.

Know anything about the Bohemian Club? Email acain@businessinsider.com.