This image shows the iconic Houghton Portage Bridge which connects the cities of Houghton and Hancock in Michigan's Upper Peninsula. This bridge contains two decks and can be lifted to allow ships to pass underneath. When copper mining was still a big industry in this area, the lower deck connected to rail lines while the upper deck was used for automobile traffic. Today, the rail lines have been removed and the lower deck is used for automobiles, but the bridge is lifted to allow most boats to run underneath. In the winter, the bridge deck is lowered and the bottom is used to allow snowmobiles to cross, while the upper level is used for automobiles.