Where others see massive towers meant only to manage the torrent of airplanes coming into and going from airports, Carolyn Russo sees beautiful structures meant to be appreciated. The photographer has spent nine years capturing a total of 85 airport towers in 23 countries for her upcoming book, Art of the Airport Tower (Smithsonian Books, $30), which shows the evolution of the air traffic control tower. From advances in engineering with the angles of the tower’s glass to the modification of the structural support, Russo documents how these “lifeguards of the sky” are as symbolic as they are significant throughout the world. Pictured here is Stockholm-Arlanda Airport (ARN), Sweden.

Abu Dhabi International Airport (AUH), United Arab Emirates.

Ronald Reagan Washington National Airport (DCA), Virginia, United States.

Fort Worth Alliance Airport (AFW), Texas, United States.

LaGuardia Airport (LGA), New York, United States.

Edinburgh Airport (EDI), Scotland, United Kingdom.

John F. Kennedy International Airport (JFK), New York, United States.

Dubai International Airport (DXB), United Arab Emirates.

Amsterdam Airport Schiphol (AMS), Netherlands.

Bangor International Airport (BGR), Maine, United States.

Birmingham Airport (BHX), United Kingdom.

Barcelona El-Prat Airport (BCN), Spain.

Dubai World Central-Al Maktoum International Airport (DWC), United Arab Emirates.

Art of the Airport Tower (Smithsonian Books, $30).