Highway to the Sun Traveling I-75 from industrial parks to the grasslands In the twilight of a rainy evening, Sault Ste. Marie, Mich., gives visitors a chill. Yellow lights try to break through the gloom, but the mist mutes them, as if the weather is determined to dampen spirits. On the Canadian side of the St. Mary's River, smoke stacks puff endlessly. Towers of steel and concrete rise along the waterfront, turning river banks into industrial parks. On the American side, rain slicks quiet downtown streets and store windows invite pedestrians inside, into their warmth. Cars line up at the border in the shadow of the 2.8-mile International Bridge. Flags of both nations flutter at the border midway across the span. This is where the road begins. Fast forward 1,775 miles south to a dramatically different landscape. Through the Everglades travelers go, a blazing sun warms dashboards and faces. Hawks circle overhead. Egrets perch on trees. Alligators sun themselves beside canals. Grasslands stretch to the horizon, devoid of human life. From this wilderness, buildings and highway mazes appear on the horizon. A few miles away, but still out of sight, Miami beckons with its perpetual sunshine and upbeat Latin music. This is where the road ends. In between lie sprawling cities and quiet farmland, steep hills and prairie-like flatlands. Towns on technology's cutting edge and towns that eschew the commotion such gadgets bring. The communities are entirely disparate - except for one thing: They are sprinkled along Interstate 75. Communities depend on it. Yet sometimes their residents curse it. For 25 years now, the highway has connected residents of six states - Michigan, Ohio, Kentucky, Tennessee, Georgia and Florida. Some places have lived with it since the 1950s when Dwight D. Eisenhower envisioned the country's interstate system. Others, namely Florida, have lived with it for less than 20 years and still watch its influence shape it.