Spirit Cave (Tham Phii Man in Thai) is an archaeological site in the hills north of Soppong that was excavated in the 1960s and produced evidence of some of the earliest known plant cultivation in Southeast Asia. The cave itself is a relatively modest rock shelter, but the stone tools, plant remains, and human bones found here transformed understanding of early agriculture and human settlement in the region.
Getting to Spirit Cave requires a guide and some hiking through the forested hills — the site is not set up for easy independent visitor access. The local guide organizations in Soppong and Tham Lot can arrange tours. The cave is less spectacular visually than Tham Lot but more significant historically, and the walk through the forest and hills is rewarding in its own right.