landmark vs mile marker

landmark

noun
  • A recognizable natural or man-made feature used for navigation. 

  • An object that marks the boundary of a piece of land (usually a stone, or a tree). 

  • A major event or discovery. 

  • A notable location with historical, cultural, or geographical significance. 

verb
  • To officially designate a site or building as a landmark. 

mile marker

noun
  • A numbered milepost or sign along a highway, or some other road, used to determine the location of a motor vehicle. 

How often have the words landmark and mile marker occurred in a corpus of books? (source: Google Ngram Viewer )