HOK International is an international design, architecture and engineering firm that was founded in 1955 in St. Louis, Missouri by George Hellmuth, Gyo Obata and George Kassabaum. 

Since the 1960s, the firm has been awarded numerous commissions throughout the United States and it opened its first branch office in San Francisco in 1966. HOK International has distinguished itself over the years as a leader in the area of sustainable design, and has realised important projects including the Priory Chapel in St. Louis, the National Air and Space Museum in Washington, the Tokyo Telecom Center in Tokyo, the Kellogg Company headquarters in Battle Creek, Michigan, the Amsterdam Passenger Terminal in Amsterdam, the Indianapolis International Airport Colonel H. Weir Cook Terminal in Indianapolis, Indiana, the Salvador Dali Museum in St. Petersburg, Florida and the King Abdullah University of Science and Technology in Thuwal, Saudi Arabia. The firm has offices in the United States, Canada, Asia, Europe, India and the Middle East.

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