The cave complex at the base of Doi Luang Chiang Dao is one of the most atmospheric temple sites in northern Thailand. The illuminated section runs about 200 metres into the mountain, past limestone formations and Buddhist shrines, ending at a reclining Buddha — you can walk this yourself for 40 THB. The deeper section (an additional 150 THB) requires a guide with a kerosene lantern and involves tight passages and absolute darkness; it's genuinely impressive and nothing like the lit tourist cave.
The cave is set within a temple compound full of carved Buddhas, spirit houses, and monks' quarters. Arrive early to avoid groups from Chiang Mai. Open daily 7am–5pm.