A total solar eclipse will cross the entire country for the first time in 38 years, on Aug. 21. The last total solar eclipse was on Feb. 26, 1979. Solar eclipses happen when the moon moves between Earth and the sun, casting a shadow over Earth. Looking directly at the sun without the correct eye protection, even for a short time, can cause permanent damage to your retinas. Ensure that you have the proper eye protection for viewing during the event. The U.S. Army Corps of Engineers St. Louis District invites the public to view this rare and cosmic event at St. Louis District sites.