Mark your calendars for Aug. 21, 2017. That's when all of North America will get a once-in-a-lifetime glimpse at a total solar eclipse.

The Great American Eclipse, as its been dubbed, will be visible to millions across the United States for the first time in nearly four decades. It will mark the first time this century a total solar eclipse will cross through the contiguous United States. It's also the first time the shadow track, called the path of totality, will sweep across the U.S. and no other country. About 200 million people will be able to reach the path of the eclipse, which will sweep the nation from South Carolina to Oregon, within a one-day drive.

Officials in Hopkinsville, Ky., are calling it the largest event to hit the town of 32,000. The town will experience the longest period of totality of any city at 2 minutes and 40 seconds. City leaders are anticipating up to 50,000 visitors will bring some $23.6 million into the area. They recently unveiled the city's logo for the event and are planning for days-long festivities.

"It is a unique opportunity and it's our great excuse to roll out the red carpet and be the best version of Hopkinsville we can possibly be," said Mayor Carter Hendricks. "Science has given us the best viewing location just north of Hopkinsville. It is up to us to promote properly so people want to come and be here."