It was built with 30 gondolas, but it was badly damaged during WWII, and only 15 gondolas were replaced when it was restored. The wheel is propelled by a circumferential cable that exits the wheel and goes through the driving mechanism under the base, and its spokes are tensioned steel cables. It can carry up to 600 passengers per hour. The Wiener Riesenrad is one of the most famous landmarks in Vienna. Its three tall wheels are surrounded by a large public park where many festivals are held throughout the year. The Wiener Riesenrad is very accessible: there are several ways to reach the top of the wheel for visitors to enjoy the view. The ride itself is very exciting and fun! The name "Wiener Riesenrad" means "Viennese giant roller coaster". It opened in 1935 and is still operating today after being rebuilt after war damage. During its lifetime it has carried more than 7 million passengers who have enjoyed its thrilling rides. The Wiener Riesenrad is made of steel and concrete. It is based on an American invention called a "hyper-cycle" which uses bicycles as a support structure for another vehicle to travel along. In this case, it's a car that uses electric motors instead of gasoline engines which allow it to travel much faster than a traditional bicycle-based contraption.