Sentence:  As he taxied out to the far side of the field, 38-year-old Captain Benton R. ("Lucky") Baldwin was cleared for takeoff. The <WSD>control tower</WSD> gave him his choice of two runways—No. 13 or No. 18. 
Meaning of the word marked with <WSD> tags:  An airport building from which the air traffic control unit monitors and directs the movement of aircraft on and around the airport.