Lake Superior

Lee Radzak is retiring this month after 36 years as manager of an iconic northern Minnesota lighthouse. Split Rock on Lake Superior attracts about 2,500 visitors a day during the summer.

Scientists say lake herring, a key fish in Lake Superior's food web, is suffering because of mild winters and Europe's appetite for roe. Some say the species may be at risk of "collapse."

Pickup truck-size ice chunks have left the freight ships stuck in Lake Superior. The U.S. and Canadian coast guards have sent in icebreakers to help the ships get through.

On the shores of Lake Superior, a man built an unusual ice sculpture using a unique robotic sprayer system. But after warm weather caused its collapse, the sculptor is determined to rebuild.