NASHVILLE, Tenn. – A total solar eclipse will bring a brief period of darkness during the middle of the day to millions in the United States on August 21, 2017.

This will be the first time since 1918 that the path of a total solar eclipse will cross the entire contiguous U.S.

A total eclipse of the sun happens when the moon completely blocks the visible solar disk, casting a shadow on Earth.

The path of totality refers to the area where the solar disk is fully blocked by the Moon, briefly creating near-total darkness.

Nashville, Tennessee, and Greenville, South Carolina, are two of the largest cities closest to Huntsville which are in the path of totality.

The sky will go dark in Nashville for around two minutes just before 1:30 p.m. on Monday, August 21 during the eclipse.

To see a chart from NASA which lists the moment of mid-totality and the duration of totality for a handful of cities that lie close to the center of the path, click here.

The sun will be at least 90 percent blocked out in Huntsville, Birmingham, and Atlanta.

Traffic nightmare

August 21, 2017, may be one of the worst traffic days in national history, some NASA representatives predict.

Although about 12 million people live within the narrow band of totality, approximately 25 million reside within a day’s drive of it, and the agency has estimated that the population inside the path of totality may double on the day of the eclipse, according to Space.com.

A clear sky will be needed for best viewing of the eclipse.

The next total solar eclipse to cross the United States won’t happen until April 2024.