Standing stones are among the most enigmatic of Ireland's prehistoric monuments: single upright blocks, sometimes barely knee-height, sometimes towering overhead, erected during the Bronze Age or earlier for purposes that remain genuinely unclear. Boundary markers, astronomical alignments, commemorations of the dead, territorial signals, focal points for ritual, all have been proposed, and none has been conclusively ruled out. The stones tend to endure not because anyone has looked after them, but because a large lump of rock in a field is simply easier to leave alone than to remove.