This is the 4th tower I've seen in the US. The first one was in Seattle, Las Vegas, and in San Antonio. This tower is located in Dallas, Texas. It's called the Reunion Tower.
According to Wikipedia, Reunion Tower is a 561 ft (171 m) observation tower and one of the most recognizable landmarks in Dallas, Texas. Located at 300 Reunion Blvd. in the Reunion district of downtown Dallas, the tower is part of the Hyatt Regency Hotel complex, and is the 15th tallest building in Dallas.
The tower consists of three floors with circular floor plans on top of four shafts of poured-in-place concrete. A central cylindrical shaft houses stairs and mechanical equipment. Three rectangular shafts, containing elevators, rise parallel to the central shaft. Each shaft's outfacing wall is made up of glass panels, affording views of the city during the 68-second elevator ride to the top.
I wish we had enough time to stroll around downtown Dallas. We went there for a short time that's why we never get a chance to climb up to the tower.