From ancient Funan to the Siamese kingdom of the current Chakri dynasty, Thailand has had its huge share of diverse monies—a wide variety of oddities in the field of ethnographic numismatics. At the Bangkok Coin Museum, an institution run by the Treasury Department, curious visitors can learn the fascinating history of Thai currencies. Despite its proximity to the National Museum and the Sanam Luang Park, it’s a lesser-known and under-appreciated tourist attraction, making it a neat oasis from the tropical heat and sightseeing crowds outside. At first glance, the museum…