How Many People Does It Take To Spin the Largest Prayer Wheel in the World?

In Buddhism, a prayer wheel is used as an instrument in prayer. It says that it is has the same merit as a mantra and has purification benefits. And Buddhists use this constantly from the moment they wake up until night. But how about having a huge prayer wheel like this one in Shangri La, Yunnnan, China? It takes several people to move this one and my aunt told me that it is really a heavy one.