The Olympiaturm (Olympic Tower) in Olympiapark (the Olympic Park), was built for the 1972 Summer Olympics. It has an overall height of 291 m and a weight of 52,500 tons. At a height of 190 m there is an observation platform as well as a small rock and roll museum housing various memorabilia, which is signposted as "Rock Museum" outside the entrance . Since its opening in 1968 the tower has registered over 40 million visitors (as of 2010). At a height of 182 m there is a revolving restaurant that seats 230 people. A full revolution takes 53 minutes. The tower also serves as a broadcast tower, and has one Deutsche Telekom maintenance elevator with a speed of 4 m/s, as well as two visitor lifts with a speed of 7 m/s which have a capacity of about 30 people per car. The travel time is about 30 seconds. The tower is open daily from 09:00 to 24:00 hrs