If there were one experience I would recommend to visitors, it would be the Tosirak cafe in Tongin Market. Tosirak means lunchbox in Korean and what people do at this cafe is to purchase a set of gold coins (I kid you not) which can be exchanged for food/side dishes at selected stalls below the cafe. The stalls participating in this cafe's concept have signs like the one in the picture. It's an incredibly refreshing adventure that everyone should try!