On December 1, 1961, a 12-foot-high double-barred cross weighing more than 600 pounds was hoisted to the 53rd floor of the east tower. It was installed in a south-facing door of the tower core. The illuminated red sign promoted Christmas Seals for the Tuberculosis Institute of Chicago and Cook County. (Left) Chicago Daily Tribune photo of cross being hoisted. The hand reaching out through an opening in the tower core belongs to Ed Tyrrell. The double-bar cross is now the symbol (below) of the American Lung Association.

Early in January of the next year, the idea of a beacon and “range lights,” a pair of lights used for navigation, was being discussed for Marina City. John Magill, a columnist for the Chicago Daily Tribune, proposed it. Mayor Richard J. Daley responded by saying it was a “good idea.”

Then in October 1962, Chicago’s first commercial television station, WBKB (now WLS-TV), announced it would erect a 426-foot tower (285-foot mast supporting a 140-foot-six-inch antenna) on the west tower. 969 feet above ground, the top of the tower would be the highest point in Chicago. It was a rental agreement worth $1 million to Marina City, equal to $7.8 million in 2014.

(Above) WLS tower in summer 1967, from roof of west tower at Marina City. Photo by Douglas Pierce. (Left) View from southeast with two towers in place on east tower. Photo by Portland Cement Association.

The tower, built in 1964, featured a column of red lights that flowed upward when temperatures were forecast to increase and downward when they were expected to drop. Slowly blinking lights meant a storm was approaching. Steady illumination meant no change.

Two rings of light at the base of the tower signaled victory (white) or defeat (blue) for a Chicago sports team. A third ring represented the WBKB “Circle 7” logo.

The beacon was designed, built, and maintained by White Way Electric Sign & Maintenance Company of Waukegan, Illinois (now in Mount Prospect). It was controlled from WBKB studios at Marina City.

WBKB started broadcasting from Marina City in September 1964. In 1974, WLS moved its television transmitter from Marina City to Sears Tower. Mayor Daley threw a ceremonial switch and the station went off the air momentarily, then came back with a poor signal from Sears Tower said to be almost unwatchable.

According to Mike Wilson, an engineer for KTLA-TV in Los Angeles, who worked at WLS while attending college in Chicago at the time, there had been an error in the construction of the new transmitter or antenna at Sears Tower. The station switched back to the Marina City antenna until the problem was corrected.

(Above) In July 1964, Chicago Tribune photographer Jack Mulcahy (far left) climbed 150 feet up the uncompleted mast on the west tower at Marina City. Ironworker Blackie Barnhill, who took the photo of Mulcahy, assisted him. At center, a photo of Blackie taken by Mulcahy. At right, a closer angle of the mast and antenna at the top of the tower.

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(Right) A man climbs a television mast that added 437 feet to the height of the west tower.

(Left) How the broadcast tower sat on the west tower roof in 1966. This is from the east tower roof, looking northwest. Merchandise mart is visible in distance. Photo by Michael Leonard.