A communications and observation tower in Toronto, Ontario, Canada.

A crane, consisting of a balanced beam erected on top of a tall metal (normally self-erecting) tower, used in the construction of tall buildings

Alternative form of Leaning Tower of Pisa

A watchtower to search for fires in a forest. / In a high building, a stairway protected by several inches of concrete and entered through a kind of "air lock" that prevents the smoke to enter inside it.

Synonym of watchtower

In a high building, a stairway protected by several inches of concrete and entered through a kind of "air lock" that prevents the poluted smoke to enter inside it.

(aviation) An airport building from which the air traffic control unit monitors and directs the movement of aircraft on and around the airport.

A bascule bridge in London crossing the River Thames, built in the late 19th century

(physics, engineering) A tower, containing a long evacuated tube, within which objects can be dropped experimentally. / An amusement ride in which riders experience free fall.

(mathematics) A chain of exponentiations, or raising to powers, of the form a^(aa...); tetration.