landmark (n.)youdaoicibaDictYouDict[landmark 词源字典]
Old English landmearc, from land (n.) + mearc (see mark (n.1)). Originally "object set up to mark the boundaries of a kingdom, estate, etc.;" general sense of "conspicuous object in a landscape" is from 1560s. Modern figurative sense of "event, etc., considered a high point in history" is from 1859.[landmark etymology, landmark origin, 英语词源]