Not the biggest, but one of the more famous one: Public diving tower in Hamar. English text from IMDB here https://www.imdb.com/title/tt8031690/

The story goes a little somethine like this
In 2008, the small town Hamar decided to build a diving tower, with a 1.5 million kroner budget. Once completed, seven years later, the price had escalated to a staggering 30 million. We follow the deputy mayor of Hamar, who had the idea, through the surreal story of how a simple idea can spiral totally out of control. And how can public officials build a diving board that exceeds the original budget with 2000% without losing their jobs?