There were about 160 lava tubes on Jeju Island. Manjanggul Lava Tube was the biggest at over seven kilometres in length. It was formed between 1 000 to 3 000 years ago when Geomunoreum volcanic crater erupted. Near Manjanggul, four other lava tube caves were formed, but only Manjanggul was open to the public.
I was overwhelmed by the sheer size of the lava tube that was twenty-three metres at its widest and thirty metres at its highest. After I ventured a couple of hundred metres into the tube an Australian tourist said there was no point going any further because it was all the same. But she was wrong. There were lava stalactites, lava flow lines, lava shelves, ropy lava and a lava column at the end of the one kilometre trail — the distance we were allowed to explore. I was in awe with every step I took over the uneven and sometimes slippery floor.