[just found this unpublished post] … or Sangdang Mountain Fortress is a stone wall high up on a hill just outside Cheongju. It’s girth is about 4 km and it took us just little more than one hour to walk around it. Take bus number 862 or a cab – but make sure you know how to call it when you want to get back down. The easiest way is to call your hotel and let them do the talking. If you’re really keen you can walk back to town which probably takes another hour or so, haven’t done it myself though. Hint: if you choose to walk anti-clockwise you’ll have to ascend some steeper hills but the good thing about it is that almost all Koreans decide to walk the other way so you don’t feel like a herd animal – and on a sunny day it can get really crowded up there!