It begins rather innocently.

An infectious track, a conservative, solo dancer and a few oblivious observers.

A mere fifteen seconds of pelvic thrusts, then, a roar of a lion, a drop of a beat...

Then, everyone goes CRAZY.

The "Harlem Shake" is the No. 1 song on the Billboard Hot 100 for the second week in a row, a top 10 iTunes download and the meme of the moment. Millions are watching variations on the "Harlem Shake" video theme in which the dance starts with one person thrusting their pelvis or dancing solo for 15 seconds, while the people in the background ignore them. Then when the beat drops, a group joins in bizarre, repetitive movements. The whole dance lasts around 30 seconds.

While this latest trend is built around the "Harlem Shake," it has scant ties with the New York neighborhood and very little in common with the original dance that shares its name.

So just how did the phenomenon begin? It starts with a dancer in Harlem, a producer from Philadelphia and ends with you.

When Harry Rodrigues, a 23-year-old producer and DJ professionally known as Baauer, released a song called "Harlem Shake" last spring, he had only briefly lived in Harlem. He told the Daily Beast that the idea for the title of the song came from Philadelphia rapper Plastic Little's "Miller Time."

"A friend had shown me that track where he says, 'then do the Harlem shake,' and it just got stuck in my head for a while, so I used it," he said in the Beast's exclusive interview.

On Feb. 2, comedian "Filthy Frank" on YouTube uploaded a video featuring people dressed in costumes doing jerk type movements to Baauer's track. Then, TheSunnyCoastSkate, a group of young men from Australia, uploaded a video that is credited with shaping the format.

The University of Georgia men's swim and dive team has done a version underwater.

The anchors of the "Today" show got in on the action with their shake.

Even the English National Ballet has a Harlem shake video.

But what does it have to do with Harlem?

To hear Harlem tell it, very little.

"How can I even think ... they were trying to mimic the Harlem shake?" said Erika Ewing, a Harlem-based actor. "Or is this their interpretation, parody and commentary on who we are as a culture and people?"

Filmmaker Chris McGuire went to Harlem to hear the reaction of Harlemites:

Some thought it was disrespectful; others were offended.

But there is one famous, former Harlem resident who supports the craze.

"I do want people to get educated on the real Harlem shake; it's something that's an art form, but anything that's branding Harlem, my hometown, I'm all for it," Sean "P. Diddy" Combs told MTV News.