Long before the more famous northern defensive walls were built, the state of Qi constructed a wall across the Shandong hills to defend against the states of Chu and Lu to the south and west. Built from the Spring and Autumn period through the Warring States period (roughly 7th–3rd centuries BCE), the Qi Great Wall runs about 618 kilometres through the Yimeng and Tai Shan ranges — predating the Qin-era northern wall by several centuries.
The best-preserved sections run through the Yimeng Mountains north of Linyi, where the stone rubble core of the wall still rises several metres above the ridge lines. Walking these sections involves genuine hill walking on unimproved trails; the wall is visible as a continuous line of tumbled stone across the horizon. This is archaeology for enthusiasts rather than casual visitors — no facilities, uneven terrain — but the sense of standing on a 2,500-year-old defensive structure that nobody maintains or promotes is its own reward.