U.S. soldiers were fighting in Korea when President Harry Truman signed a congressional resolution calling for an annual National Day of Prayer.
The purpose of the inaugural event in 1952 was for people to gather in houses of worship to pray for world peace.
Since 1988 the event has taken place the first Thursday in May. It is diligently observed by some churches and ignored by others.
The 70th edition this week comes after a year of pandemic, political polarization and turmoil related to racial injustice.
Several faith leaders say they plan to pray for unity and an easing of political and social divisions.
Events to celebrate the day are taking place across the country, click here to find one near you.
Florida Attorney General Ashley Moody will be in Tampa at a sold-out prayer brunch at Armature Works.