obelisk
An obelisk is a tall, four sided, tapered, monolithic pillar, with a pyramid shaped top, usually made of stone or concrete. Obelisks are heavily associated with Ancient Egypt and are commonplace in art evoking it (including science fiction and fantasy settings inspired by Ancient Egypt); however, obelisks are found all over the world, and used as markers, gravestones, monuments, and landmarks.
Not to be confused with Obelisk the Tormentor from Yu-Gi-Oh! or Obelix from Asterix and Obelix