In his new book, ‘Follow the Money’, author Steve Boggan followed a $10 bill around the U.S. for 30 days.

“What, I wondered, would I find out if I were to set off from the geographical centre of the continental US and follow a $10 bill for 30 days and 30 nights? Was it possible?,” he says in a story about the project in The Guardian.

He watched as the money was exchanged in transaction after transaction, and learned a whole lot about the U.S. economy in the process.

“What I had to do, before each person spent the money, they’d tell me what they were going to do, and I’d go up to the next recipient and say, “Look, this guy or this woman is about to spend this $10 bill, I’ve been following that bill and I’d like to carry on following, will you cooperate,” Boggan says.