The Korean Rail Pass is a travel pass that allows unlimited travel on most trains operated by Korail in South Korea. It is available for various durations, typically ranging from 1 to 5 days, and is ideal for tourists looking to explore multiple cities efficiently. With the pass, travelers can access high-speed trains like the KTX, as well as regular and express trains. It can be purchased online or at designated locations, making it a convenient option for those planning to visit popular destinations such as Seoul, Busan, and Incheon.