There are some very long bridges in the world. And these long bridges would certainly be measured in miles. One of these is the Hong Kong - Macau bridge in China, which is a bridge-tunnel system and also spans three islands. The length of this bridge system is 34 miles. I believe there is also a discussion underway about a possible bridge between Siberis and Alaska across the Bering Strait. This bridge would be about 50 miles in length overall.