A boy plays on a swing - Representational image REUTERS/Ricardo Moraes

About 50 rope swings popped up across the city of San Francisco last weekend, courtesy the anonymous group #SwingBombSF.

Exact locations of these swings are anyone's guess – a few have appeared on parks and sidewalks whereas others near busy urban centres. The group says it has deliberately not tagged the swings.

"We decided to create a present for the city, where it would wake up one morning and have a moment of surprise," the anonymous group told SF Weekly. The swings appeared early Saturday morning (17 February).

"It really nurtures this inner child, it's a very playful community. We wanted to play into that, and make the concept of S.F. being an adult playground into a reality."

Several delighted San Francisco residents have posted pictures of the swings on Instagram and Twitter.

"We saw this -- this swing just hanging from a tree. It was very random," said Diana Apanovich, visiting with her two daughters from San Diego, ABC news reported.

For Nick Chang and friends, the swings reminded them of their childhood.

"San Francisco at least used to be a place where, you know, inner child wanted to come out, and that's why everyone's here: we're all grown children," another resident said.


A post shared by Swing Bomb SF (@swingbombsf) on

The anonymous group says it has engineers in its team, who made sure that the trees had the structural integrity to hold the swings.

City officials are not amused though and have pulled down quite a few of these swings.

"They did not come to us for us to take a look at what they wanted to do, so that we can ascertain that this is safe," Recreation and Parks Department operations manager Dennis Kern told ABC 7.