No Bears Allowed! in the 3rd Infiltration Tunnel (or luggage, or cameras, or pretty much anything - so here is my home for 45 minutes...). However, my extremely acute bear-hearing allows me to hear the distinctive "CLUNK, ouch, swear" repeatedly as Ken bangs his head (thankfully wrapped in a compulsory hard hat) against the tunnel roof. The access tunnel is long and steep, the actual infiltration tunnel, dug by North Korean troops, is narrow and not very tall (like, we presume, the troops it was built for). It ends in an austere steel-plate with an observation hole and a rather machine-gun shaped slot (covered in "NO PHOTOGRAPH" stickers). I don't think I'd want to be a North Korean conscript coming down that tunnel thesedays....