tower

A tower is a tall structure, taller than it is wide, often by a significant factor. Towers are distinguished from masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting structures.
Towers are specifically distinguished from "buildings" in that they are not built to be habitable but to serve other functions. The principal function is the use of their height to enable various functions to be achieved including: visibility of other features attached to the tower such as clock towers; as part of a larger structure or device to increase the visibility of the surroundings for defensive purposes as in a fortified building such as a castle; as a structure for observation for leisure purposes; or as a structure for telecommunication purposes. Towers can be stand alone structures or be supported by adjacent buildings or can be a feature on top of a large structure or building.

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