Found in areas where people practise Tibetan Buddhism, mani stones are slabs of rock with engravings of buddhist symbols, images or tibetan religious script. Stacked along walls or piled up as chortens, mani stones are commonly found along trails at the approach to villages. This wall is in the Langtang valley. Believers and sensitive trekkers always pass the walls or chortens clockwise, keeping them on the right. Some of the engravings are centuries old, fading over time.