If the conspiracy theorists are on to something, they could be plotting the invasion of Iran, planning the funeral of the Euro or scheming to wipe out French poodles in pink sweaters at this very minute.
Or perhaps the world's financial and political leaders are simply schmoozing about their golf game as they enjoy a "chocolate massage" followed by the "honey body scrub" and the "spectacular oxygen Echo2 facial" at the Dolce Hotel's spa in Sitges.
It is also possible that the world's executives, media moguls, and financial gurus came to the elegant seaside town near Barcelona to study the booming gay tourist market there (although they missed the wild Carnival celebration by a few months) and to sneak a preview of next year's international horror film festival.
But ordinary citizens can only guess at the goings-on at the annual meeting of the secretive Bilderberg Group, a media-barred pow-wow of the global elite that in the past has reportedly attracted former US President Bill Clinton, Tony Blair and David Cameron, and US treasury secretary Timothy Geithner. Even the late Enoch Powell once attended.
The heavyweight weekend retreat kicked off yesterday with hordes of police security and a gag order for employees at the luxury Dolce, whose aptly-named presidential suites overlook the Mediterranean. None of the illustrious guests posed for photos or spouted prepared statements for the media. Instead, activists, journalists and bloggers attempted to stake out positions in the surrounding hills to catch glimpses of this year's participants, guerrilla-warrior style.
"We just dropped two people by the hills and they are trying to run for cover so they aren't spotted by the snipers," said Hannah Borno, co-founder of an activist agency, Trilever, which is calling for transparency on the Bilderberg deliberations and offers information (also known as leaks) to the press. "I hope they're OK."
Ms Borno paid €135 for the hotel's cheapest room for the chance to see the preparations – as well as swarming secret service agents – before being forced to leave for a nearby campsite, surrounded by police. Overhead: a no-fly zone.
"The public is paying for this security," she added. "I can see 20 to 30 police vans right now. We are offering a pro-bono lawyer in case any of the activists or bloggers are arrested."
Some people consider the Bilderberg Group, founded in 1954, an innocent brainstorming session, but the cloak-and-dagger theorists scored a point this week when the self-appointed Bilderberg expert Daniel Estulin addressed the European Parliament on the invitation of an Italian member, Mario Borghezio.
Mr Estulin, an investigative journalist who has written two best-selling books on the subject, contends that "the Bilderberg Club" is not a classic conspiracy but a potentially dangerous meeting of minds with a common goal: to centralise global economic power to benefit corporations. He defined it as "a virtual spider web of interlocking financial, political and industrial interests".
"It isn't a secret society," he said. "No matter how powerful they are, no group sits around a table holding hands and deciding the world's future. It is an ideology."
Secret society or not, the speculation surrounding Bilderberg rivals the eternal question of who shot JFK – to the extent that one Spanish activist vowed he has sighted freemasonry symbols on the Sitges hotel. Being the meeting is secret, it is impossible to confirm which executives and lawmakers have checked into the spiffy Dolce, in the heart of golf-and-sunbathing territory. Politicians often deny participation. But according to press leaks, this year's A-list participants include Queen Beatrix of Holland, Spain's Queen Reina Sofia (supposedly a regular), World Trade Organisation Director Pascal Lamy, European Central Bank President Jean-Claude Trichet, former NATO chief Jaap de Hoop Scheffer and former Spanish vice president Pedro Solbes, known during his stint as an EU commissioner as "Mr Euro".
Meanwhile, Extremadura Progresista, a left-wing newspaper from Extremadura, one of Spain's poorest regions, published a list of participants on its website, including former Secretary of State for Business Peter Mandelson and the Chancellor of the Exchequer George Osborne (although he's currently in Asia), plus executives from Siemens AG, Microsoft, Royal Dutch Shell, Chase Manhattan Bank and Morgan Stanley International.
And what might this all-star cast be discussing between forkfuls of paella and sips of cava on a warm summer's eve? Topics reportedly include everything from the possible failure of the euro and the creation of a global currency, to a military strike against Iran.
Another issue supposedly on the agenda is the financial meltdown in Greece, where last year's brainstorming session was held. The irony is not lost on Spanish activists, who hope the Bilderberg "witches' Sabbath" does not brew bad tidings for the troubled Spanish economy. "We joke that the horror film festival is starting early," Didac Sanchez, an activist with the organisation EcoXarxa Montseny, told The Independent over the phone amid background chanting. "The monsters are here."
Thursday's protests, which attracted about 100 demonstrators, were paltry compared to previous anti-globalisation rallies in Catalonia – partly because chic-and-wealthy Sitges is not the sort of place to get ruffled about whatever a bunch of CEOs do in their spare time. But Bilderberg's low profile also played a part.
"It's so secretive that not even people in the leftist movements know about it," Mr Sanchez said. "And it's so frightening that people can't even believe that it's real. Some people theorise that they want to kill off half the world; others believe they're directing the world's finances. But we're here to say it is real, it is happening."
He expects momentum to build throughout the weekend, however. The carnival-inspired theme of the protest is "unmasking Bilderberg". "We will set up a healing camp," he said. "It will be a festival of cleansing."
Peter Mandelson, Ex-Business Secretary
Jean Claude Trichet, European Bank President
Reina Sofia, Queen of Spain
... and the alumni
Bill Clinton, US President
Tony Blair, Prime Minister
Enoch Powell, Conservative minister