at it again. Envelopes full of cash hidden in the windy city and here in new York. In fact, right down the street in central park. Mara schiavocampo, right there looking. Reporter: It's the dash for... See More
at it again. Envelopes full of cash hidden in the windy city and here in new York. In fact, right down the street in central park. Mara schiavocampo, right there looking. Reporter: It's the dash for cash. Sweeping the country. Countless treasure hunters scouring their city for some extra bills. I'm trying to find the hidden cash. Reporter: It all started as a social media experiment. Jason buzy hiding money around San Francisco last month. Posting clues on the Twitter account @hiddencash. We're doing it to give back and put smiles on people's faces. That's the point. Reporter: Those smiles spreading across the country. A total of $25,000 hidden across the United States. In at least three cities in the last eight weeks. Today, Chicago. $50! Reporter: But these finders are not always keepers. Many sharing the money with others. Like Albert, from Brooklyn. Giving his cash to a person in need. Saturday was hidden cash's biggest day yet. Hitting multiple cities at once. Houston, Mexico City, two places in New York in Brooklyn and Manhattan. Many searching high and low. No stone unturned in central park where more than $20,0,000 was hidden in 40 locations. It does bring new yorkers together. It is exciting. Reporter: Now, the jackpot might be growing. Overnight, Guzy asking others to join his cause. With this tweet -- start leaving cash in random places. Not kidding. Do it. You don't want to stop the momentum. Reporter: An unexpected windfall of cash and kindness flowing across the country. Mara schiavocampo, ABC news, new York. And the good news, more cash is coming. The bad news, you'll have to travel. Paris, Madrid, London is next.
This transcript has been automatically generated and may not be 100% accurate.