Anonymous benefactor hiding envelopes of cash around San Francisco, US

Thousands of San Francisco residents have been involved in a scavenger hunt over the last few days, as an anonymous person has hidden $100 bills around the city and posting clues on their location on Twitter.

The benefactor, who uses the Twitter handle @HiddenCash, has been hiding white envelopes containing the cash around the city since Friday, in what the Twitter account described as:

An anonymous social experiment for good

The person behind the tweets, who wishes to remain anonymous, told SFGate in an email interview that he decided to use some of the half million dollars he had just made in a real estate deal for a fun game for fellow residents of the city. He may even expand the game to other cities, saying:

I have no plans to stop anytime soon. In fact, we will also drop some in L.A. next week (I am going there on business). Any maybe expand to more cities.

Could you and 25 of your friends use a @Sightglass Coffee? Look in the abandoned phonebox next door. pic.twitter.com/tzh9Ffk6dt

— Hidden Cash (@HiddenCash) May 23, 2014

New drop: Mint Plaza. Under the orange chair closest to Blue Bottle coffee. Tweet when you find it :) pic.twitter.com/3uE7S7m8DH

— Hidden Cash (@HiddenCash) May 23, 2014

New Drop: Giving Oakland some ❤️. Lake Merritt BART (storage container, bikerack, tree). SF drop in 15 min pic.twitter.com/CJxCVVLkzo

— Hidden Cash (@HiddenCash) May 23, 2014

New drop: Look under me :) pic.twitter.com/QX1M6cjvGb

— Hidden Cash (@HiddenCash) May 23, 2014

Hear from one of my coworkers who found some $$$ from @HiddenCash. He'll be on @kgoradio at 4:45. Pic of envelope: pic.twitter.com/koDTthcquX

— Elissa Harrington (@EHarringtonNews) May 23, 2014