The Hidden Cash Twitter campaign, which started with an anonymous benefactor hiding money in envelopes and tweeting cryptic clues as to their location for people to find, has started to spread worldwide.

Originating in San Francisco on May 23, the first account was set up with the bio that says, “An anonymous social experiment for good. Real Cash hidden around SF & beyond. Find the $ – share tweetphoto + tag @hiddencash.” Since that first tweet, the account has grown to 405,000 followers.

The craze then went to San Jose, followed by Los Angeles over the weekend. On Saturday, beaches were flooded with people looking for angry bird heads stuffed with cash. The generous donor said he will soon be heading to New York City.

Hermosa Beach between the pier and the volleyball nets to your left (as you face ocean). Remember -there are 36! Go! pic.twitter.com/VjGY1X7VcB

— Hidden Cash (@HiddenCash) May 31, 2014

Cities across the United States now have their own Hidden Cash benefactors — From Nashville, to Dallas, to Oklahoma City, to name a few.

Getting ready for tomorrow's EPIC beach scavenger hunt.Pop open the bottom with ur nails. #angrybirdsstuffedwithca$h pic.twitter.com/TOYBLL6O53

— Hidden Cash (@HiddenCash) May 31, 2014

The benefactor asked people to pay it forward on Twitter and it looks like others around the world are heeding his words. An account – called @HiddenCash_UK – was set up in the United Kingdom on Tuesday.

The anonymous rich person that's been hiding money places is now driving LA crazy http://t.co/vh1Mza4Pmh pic.twitter.com/LlaQUTcBd0

— Huffington Post (@HuffingtonPost) May 30, 2014

First ever San Jose drop: across from where these sea creatures play, a dog pees in the fall. pic.twitter.com/O3IrpfmPbp

— Hidden Cash (@HiddenCash) May 28, 2014

Stuffing birds. Bring the choppers, bring your kids, bring your friends to the beach 2mrw. This will be FUN. 11 AM. pic.twitter.com/bNFiRavqrQ

— Hidden Cash (@HiddenCash) May 31, 2014

The account has so far tweeted clues to the location of four envelopes containing £50. They were found by people in Leeds, Sheffield, Manchester and Brighton.

There are other accounts popping up as well in Canada, Hong Kong, The Netherlands, and Ireland, and more are cropping up by the day.

Little is known about the original benefactor, other than he or she is a rich property mogul who feels bad about the discrepancy between rich and poor in San Francisco.

In several anonymous interviews, “Hidden Cash” has said that he/she is aged between 35 and 45 and is a real estate developer who recently made $500,000 “flipping” a house in San Francisco.

“There is nothing commercial behind this. I’ve made millions of dollars the last few years, more than I ever imagined, and yet many friends of mine, and people who work for me, cannot afford to buy a modest home,” said the mysterious benefactor. “This is my way of giving back to the community and also having fun.”

Image via Twitter, Hidden Cash