Wikipedia
A jjimjilbang (; ) is a large, gender-segregated public bathhouse in Korea, furnished with hot tubs, showers, Korean traditional kiln saunas and massage tables. Jjimjil is derived from the words meaning heating. However, in other areas of the building or on other floors there are unisex areas, usually with a snack bar, ondol-heated floor for lounging and sleeping, wide-screen TVs, exercise rooms, ice rooms, heated salt rooms, PC bang, noraebang, and sleeping quarters with either bunk beds or sleeping mats. Many of the sleeping rooms can have themes or elements to them. Usually jjimjilbangs will have various rooms with different temperatures to suit guests' preferred relaxing temperatures. The walls are decorated with different woods, minerals, crystals, stones, and metals. This is to make the ambient mood and smell more natural. Often the elements used have traditional Korean medicinal purposes in the various rooms.
Most jjimjilbangs are open 24 hours and are a popular weekend getaway for Korean families. During the week, many hardworking Korean men, whose families live out of the city for cost savings, stay in jjimjilbangs overnight after working or drinking with co-workers late into the night. The cost is around 8,000-12,000 won to enter, and one can sleep overnight and enjoy the bathhouse and sauna.