Alpena, Michigan, United States

Alpena is a small Michigan city on the shores of Lake Huron that harbors one of the Great Lakes' most extraordinary underwater treasures — the Thunder Bay National Marine Sanctuary, protecting over two hundred shipwrecks in waters so clear and cold that vessels sunk over a century ago remain eerily intact on the lake floor.

The marine sanctuary encompasses 4,300 square miles of northwestern Lake Huron, where the convergence of shipping lanes, unpredictable weather, and rocky shoals created a 'Shipwreck Alley' that claimed hundreds of vessels from the 1830s through the early twentieth century. The Great Lakes Shipwreck Museum in Alpena's Great Lakes Maritime Heritage Center displays artifacts and provides interpretive context for the wrecks, while glass-bottom boat tours and scuba diving excursions offer direct encounters with vessels preserved by the cold, fresh water in conditions that saltwater environments cannot match.

The most accessible wrecks lie in shallow water near the shoreline, their hulls visible from the surface on calm days. The deeper wrecks — some resting in over a hundred feet of water — preserve entire vessels: wooden schooners with their masts still standing, steamships with their machinery intact, and the personal effects of crews who went down with their ships in storms whose violence is difficult to imagine from the pleasant summer shoreline.

Viking includes Alpena on Great Lakes itineraries, with the marine sanctuary providing a unique port experience that combines maritime history with underwater archaeology. The surrounding area — the limestone karst landscape of Rockport State Recreation Area, the historic commercial fishing village of Rockport, and the dark-sky viewing opportunities that Michigan's northern Lower Peninsula provides — offers additional diversions.

June through September provides the best conditions, with July and August offering the warmest water temperatures and calmest lake conditions for glass-bottom boat excursions. Alpena proves that the Great Lakes' most compelling destinations are often the least expected — a small Michigan city that sits atop one of North America's most remarkable underwater museums.