Welcome to Gubeikou
The historic, far-flung town of Gǔběikǒu (古北口; ¥45 through ticket, ¥20 town only) is just an ever-expanding village these days, but was once an important, heavily guarded gateway into Běijīng from northeast China. The village, split into two sections by a ridge, with the Great Wall running along it and a small tunnel running through it, contains plenty of old courtyard homes (plus lots of rebuilt ones) and half a dozen small temples. Various stretches of the Wall meet in and around the village, in a kind of Great Wall crossroads with lots of hiking options. One short stony stretch of wall dates from the far-off Northern Qi dynasty (AD 550–577). The other stretches are Ming. There are well-worn dirt pathways on or beside them, so hiking here isn't as dangerous as it can be at other unrestored sections of the Wall. You should still take great care, though.