DeletedUser
An idea could be the "Tower of Victory and Peace" from Ottawa, Canada -- or any other clock tower. The purpose is that one of the bonuses works in conjunction with other GBs. Effectively it lessens the amount of time needed for a GB reward. Instead of 24 hours it cuts it down by percentage or straight hours as it levels up. Instead of 24 hours before a GB resets it only takes 23, then 22, and so on.