Don't wonder why the Aerial Lift Bridge is dark Saturday night.  Duluth will participate along with millions around the world on Saturday, March 29, 2014 starting at 8:30 p.m. to commemorate Earth Hour. For one hour, the lights on the Lift Bridge will be turned off as a demonstration of our support and commitment for sustainable practices to protect our precious natural resources. The City encourages the community to participate in this grassroots worldwide movement.