Human-created formations, cairns come in various shapes, styles, and categories. Rock piles and single stones used to mark the places of the dead are among the most widely known. These include the menhirs, dolmens, and barrows of Western Europe; the stupas of Buddhist Asia, along with the stelae and obelisks of other cultures; and myriad memorials and markers down to the humblest gravestone and the simplest pile of hand-placed stones at a burial site. In its usual, restricted sense, cairn refers only to the (most often) conical pile of stones used to mark boundaries; turning points along routes of travel; caches of food, water, and equipment; areas of danger; sacred sites; and places of private or personal importance. In a less restricted sense, cairn is applied in North America to the burial and efﬁgy mounds, medicine wheels, herding chutes, stone ﬁgures (for example, inuksuit), ground glyphs, and other stone structures created over many thousands of years by the Native peoples of the continent. Many of these sites are protected; others await the recognition that will afford them protection. Meanwhile, one stone atop another says a human being was here, feeling, thinking.