Every winter, ice provides a vital link to the mainland. Two hundred years ago, British soldiers used teams of oxen to haul men and materials across the ice when they moved Fort Michilimackinac from the mainland to the island. In the later 1800s, the weekly mail was brought by dogsleds and horse-drawn cutters were used to haul firewood from neighboring islands. Today, islanders anxiously wait for the Straits of Mackinac to freeze. Bitter cold and calm winds in January combine to form a solid sheet of ice. A path to St. Ignace, called the "ice bridge," is marked with leftover Christmas trees and becomes a busy highway for island snowmobilers, skiers, and walkers.