Great-Lakes Facts

Lake Michigan turned crystal clear turquoise in April 2015. A Coast Guard helicopter crew spotted something incredible on patrol. Complete century-old shipwrecks sat visible on the lake floor below them. The James McBride was a 121-foot brig that sank in 1857. It rested in 5 to 15 feet of water. Nearby, the Rising Sun wrecked in 1917 with all 32 aboard rescued. The lake holds an estimated 1,500 shipwrecks, and several remain unidentified.

Duluth's Aerial Lift Bridge doesn't tilt or swing. Its whole 386-foot span shoots 126 feet straight up in a minute, opening 141 feet of clearance for 1,000-foot ships. Built as a transporter ferry in 1905, it became a lift bridge in 1929. Ships blast a long-short-short Captain's Salute; the bridge answers back. It still does this for almost 900 ships a year, carrying 35 million tons of cargo.