The frequency and magnitude of tidal flooding of the lagoon and city of Venice have increased dramatically for over 100 years. This trend can be attributed to past periods of accelerated subsidence and present sea level rise. This flooding disturbs commerce, life and seriously damages the infrastructure of the region. The solution to the problem is a series of gates across the three inlets of the lagoon of Venice. These gates separate the Adriatic from the lagoon in periods of very high meteorological tides and stops flooding. The construction of the multi-billion-dollar system is almost completed and represents an engineering and science marvel. It has been a long road, involving innovative and creative engineering, political intrigue and scandal, and triumph and vindication for the design. This talk presents the problem, discusses why the particular solution was chosen, illustrates the elements of the built system and discusses the political, social and management issues that threatened completion and the long-term survival of the city.