The control tower at Stockholm Arlanda Airport. (Carolyn Russo / Smithsonian National Air and Space Museum)

“What’s up with these towers?” photographer Carolyn Russo joked at a preview of “Art of the Airport Tower,” her exhibition at the Smithsonian’s National Air and Space Museum. “Clearly a midlife crisis.”

Russo, who has worked at the museum since 1988 as staff photographer and art collection specialist, has been using her vacation time and weekends to chronicle as many airport control towers as possible, documenting their variety but also celebrating their sometimes abstract archaeological sweep.

Largely eliminating human figures (and planes as well), the photos, also captured in an accompanying book, are mostly black-and-white, or with colors so subdued they would seem so.

“I didn’t want them to look like lighthouses,” Russo says of the flight beacons.

Here are some numbers about the exhibition:

50

Images displayed in the exhibition; twice that many are in the book.

85

Number of airports Russo visited for “Art of the Airport Tower.”

23

Number of countries Russo visited for the project.

9

Years that the photographer has worked on the project.

1st

Place of New York’s LaGuardia Airport in the order of control towers photographed. Its distinctive ice-cream-cone look was designed by Wallace K. Harrison. Built in 1939, it was replaced by a taller tower in 2010 but not completely demolished.

5

Number of rings atop the Sydney (Kingsford Smith) Airport tower in Australia, to echo the interlocking rings logo of the 2000 Olympic Games that would be held there.

2,500

Approximate number of words in the excerpts from Antoine de Saint-Exupéry’s 1929 aviation book “Southern Mail” that adorn bands around the control tower at Stockholm Arlanda Airport in Sweden.

2

Number of protective ravens from Nordic mythology, named Hugin and Munin, that are represented by lookout points atop Sweden’s Stockholm Arlanda Airport.

2

Number of stories in the long-closed art deco-style Grand Central Air Terminal in Glendale, Calif., where the control tower was built at the northwest corner. It’s now being renovated into offices for Walt Disney Co.

2009

The year the original tower at Wittman Regional Airport in Oshkosh, Wis., was demolished, making way for one twice its height. Its demolition is chronicled in a series of Russo’s photographs.

2

Number of famous architects who designed towers at Washington-area airports: Eero Saarinen’s 1962 tower at Dulles International Airport, whose functions have been taken over by a taller tower, and Cesar Pelli and Associates’ 1997 replacement tower at Reagan National Airport.

438.9

Height, in feet, of the tallest control tower in the world, the west tower of the Kuala Lumpur International Airport in Malaysia.

12

Months that “Art of the Airport Tower” will be on display at the Air and Space Museum.

2020

Year that the multi-city tour of the exhibition is expected to end.

6.2

The number of visitors, in millions, to the Air and Space Museum so far this year, through October.

$0

Cost to visit the Air and Space Museum.

Catlin is a freelance writer.

Art of the Airport Tower

Through November 2016 at the Smithsonian’s National Air and Space Museum, Independence Avenue and Sixth Street SW. 202-633-2214. airandspace.si.edu. Free.