A watchtower or watch tower is a type of fortification used in many parts of the world. It differs from a regular tower in that its primary use is military and from a turret in that it is usually a freestanding structure. Its main purpose is to provide a high, safe place from which a sentinel or guard may observe the surrounding area. In some cases, non-military towers, such as religious towers, may also be used as watchtowers.
A watchtower on the Great Wall of China
Saint Thomas Tower in Marsaskala, Malta
A reconstruction of a Roman Watchtower in Germany
Għallis Tower, one of the 13 de Redin towers in Malta
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.
Tokyo Skytree, the tallest tower in the world
Azadi Tower in Tehran, Iran; an example of Iranian architecture of various periods
Roman tower (reconstruction) at Limes – Taunus / Germany
Eiffel Tower in Paris