What a slowdown in international travel could mean for America's tourist hubs

Sault Ste. Marie in Michigan is a small city with a thriving economy. That's because visitors from its larger northern sister city in Ontario, Canada, keep the border town's economy humming. 

Situated on opposite sides of the St. Marys River, the U.S. and Canadian counterparts are connected by the Sault Ste. Marie International Bridge, over which thousands of vehicles pass each month. 

"It's so intertwined," said Linda Hoath, executive director of the Sault Area Convention & Visitors Bureau, who noted that many people have family members on both sides of the U.S.-Canada border. "There's no separation between the two communities," she said.