Planetariums are systems designed to teach astronomy. The first modern planetarium was built by the German company Zeiss in 1923. The number of planetariums in the United States soared as a result of the space race in the 1960s, and Japan began further developing this technology as well as built planetariums during the same period. Planetariums are places where people can watch the slow movements of the heavenly bodies compressed into a short period of time. Thanks to modern digital technology, these displays have become increasingly spectacular. The 60-square-meter Discovery Sphere at the Rahmi M. Koç Museum is 8 meters in diameter and 5.5 meters high. It seats 40 people and is open in line with the museum's operating hours.