Built three years after New York’s World Trade Center and designed by the same architect, the BOK Tower is strikingly similar to the Twin Towers in appearance and construction, but at almost exactly half the size.

Not long after the Twin Towers opened on April 4, 1973, John Williams, the CEO of Williams Companies, set his mind on creating a new tower for his company in downtown Tulsa, Oklahoma. Impressed with the towers of the World Trade Center, Williams initially considered building four small-scale replicas. That, however, would have been tricky and inefficient given the space he had to work with, so the plans were changed to focus on a single tower half the size of those in New York.

And who better to get the job done than Minoru Yamasaki & Associates, the same architects who designed the WTC? Williams’ wishes were soon conjured up by Yamasaki, staying extremely faithful to the Twin Towers design both outside and in.

Construction of the Bank of Oklahoma (BOK) Tower, formerly known as One Williams Center, was completed in 1976. At the time, it was the tallest building in the state of Oklahoma, and remained so until it was surpassed by the Devon Energy Center on September 21, 2011.

Despite no longer being the tallest building in the state, the BOK Tower remains a special and poignant landmark due to its appearance and all the associated history that goes with it. At 52 stories and 667 feet tall, the BOK Tower is almost exactly a half-size replica of the Twin Towers, both of which had 110 stories and measured 1,362 and 1,368 feet tall.

The construction of the BOK also mirrored that of the Twin Towers, with steel perimeter columns and straight vertical lines. The interior reveals further parallels, from the bi-level lobby to the marble walls and even the wall hangings. Such were the similarities that executives in the BOK once joked that the architect had simply shrunk his blueprints.

Since 9/11, of course, the building has become inextricably linked with the tragedy and pain of the World Trade Center attacks. In August 2011, The New York Times asked Keith E. Bailey, the former chief executive of the Williams Companies, about the connection between the buildings. His reply: “You never realize until something like that how interconnected we are.” Williams, along with a team of employees, had visited the World Trade Center on September 10, 2001, just one day before the Twin Towers were destroyed.