ATM, there are a number of ebay listings listings for uncirculated 1917 Costa Rica 1 colón bills. They were printed by a US note company and look a lot like US

ATM, there are a number of ebay listings listings for uncirculated 1917 Costa Rica 1 colón bills. They were printed by a US note company and look a lot like US notes of the day. I don't have the history of why all these bills suddenly appeared in the market or why they were never circulated. Wikipedia notes that the Costa Rican president was overthrown in Jan of that year.