The flash-mob-style drum line was actually a pop-up teaser show by the French street performance group La Compagnie du Transe Express, which is scheduled to perform at the Kimmel Center for the Solstice in the City celebration today.
Wahl, the artistic director for programming and presentations at the Kimmel Center, said the drummers popped up to promote the upcoming show.
"We thought since they're here and they're in from France and they're never here and it's so exciting, that we would just do something to share with you what's going to happen," he said.
Josh Dubin, 33, the executive director of the skate park, was thrilled to host the group.
"I think it was the perfect example of the multifaceted uses of the park," he said.
The last time Philadelphians caught sight of the French group was during the Philadelphia International Festival of the Arts in 2011 when they dangled far above the heads of more than 20,000 people on Broad Street as a human chandelier.
For this year's act, occurring on the summer solstice, the longest day of the year, the troupe brought its drums.
"We used to close solstice with a drum circle, which is kind of an old rite, and now we are going to take that to the next level with street theater," Wahl said.
"Tomorrow night with the public! We love a lot of public," added Eleonore Guillemaud, one of the troupe's performers. "There was not enough public here for us."
The audience may have been few but those in attendance were floored. Dubin described the show as incredible.
An impressive feat considering that they had never rehearsed in the space, Wahl said.
"[The Kimmel Center audience members] are going to get on their feet and cheer! How do you not love that? It's pure joy," he said with a smile.