The world's longest lave tube formed back when Hallasan was still an active
volcano. The first kilometer of the tube/cave has been opened to the
public and makes for one of the more interesting sites in Korea. Be
sure and dress warm however - no matter the temperature outside the
Manjanggul rarely gets above 10 degrees (about 50 degrees F.) on the
inside. The path is relatively well-lit but a bit slippery from the
Transportation Car: slightly less than an hour from Cheju/Jeju City
Bus: you'll need to take a Cheju City-Songsan bus and get off at the 'Kimnyong'
exit (also marked for the caves) and switch to a local Manjanggul bus.
The local buses leave approximately every 30-60 minutes from 7:50 a.m.
to 6:30 p.m.