They said pigs would fly before Roger Waters would reunite with his old band, Pink Floyd. But pigs have been flying in Pink Floyd's world for 30 years.

When an inflatable pig escaped during Waters' set at Coachella last year, festival promoters offered $10,000 for the balloon's recovery. It might have been a "diversionary tactic," Waters told Rolling Stone, since nearby residents in the California desert were already angry that the singer's crew had disregarded warnings when they dropped a large amount of confetti over the festival. The misdirected confetti, printed with Barack Obama's name, wreaked havoc on area pool filters. Meanwhile, several pig parts were found by locals, one of which, according to Waters, was said to be wearing a Pink Floyd T-shirt at the time.

Almost three decades before Waters' appearance (and the pig's disappearance) at Coachella, Pink Floyd's then-frontman first dreamed up the image of a flying pig for the cover of the band's 'Animals' album. Hovering above London's Battersea Power Station, a massive, forbidding Art Deco-era coal-burning facility, the pig was an oddball addition to what Waters felt was the real symbolism of the picture -- Battersea's four smokestacks, which represented the band's four members "like a tortoise on its back -- not going anywhere, really."

The original airborne porker, nicknamed Algie, tore loose from its mooring on the first day of shooting for the album cover, floating dangerously into the flight path coming in and out of Heathrow Airport. Photos taken the following day of another pig featured a beautiful blue sky behind Battersea, so the band superimposed the second pig onto the gloomier (and much more apt) skyline of the first day.

Since then, various porcine balloons have flown over Pink Floyd performances across the globe, including a menacing black sow during a promotion for 'The Wall' and many others that were partially filled with propane and set on fire. At least one was no sow at all: In 1987, following Waters' acrimonious departure from the group, the remaining band members toured with an inflatable boar that featured a prominent pair of testicles. The design change, it was presumed, would preempt any attempt on Waters' part to sue for intellectual property theft.

At the Berlin Wall in 1990, Waters inflated a hog's head so big that it caused considerable damage. Floating piggies are so closely tied to Pink Floyd's legacy that one was even immortalized as a 'Simpsons' punchline: When a cartoon Peter Frampton flew a pig over a concert site, he explained that he'd gotten it at "Pink Floyd's yard sale."

And yes, Waters finally did reunite with his old bandmates, in 2005, at Live 8 in London. Proving, once and for all, that pigs really do fly.