Today, credit cards are a $500 billion-a-year industry. Banks consider these lines of credit when deciding whether or not to approve loans, incentivizing customers to maintain multiple credit cards. So, how did this lending system originate? And how did they get to be so popular? Nidhi Upadhyaya digs into the history of credit cards in the United States. Lesson by Nidhi Upadhyaya, directed by Jeff Le Bars, JetPropulsion.space.