Why do we sing the national anthem before sporting events?

Why is DeMarcus Ware singing national anthem at Hall of Fame Game? Cowboys great 'most nervous' to sing ahead of preseason game

Curb's Harper Grace Puts Artists' National Anthem Stress Center Stage – Billboard

Is the National Anthem Stupid? - The Philadelphia Citizen

Valley News - Column: Oh, Say Can You See What So Rotely We Sing?

From the archives - The history of the national anthem in sports - ESPN

What is the Black national anthem? Here's why the NFL plays 'Lift Every Voice and Sing' before games

Crowd sings national anthem after announcer says it wouldn't be played - CBS News

Sing, stand, hand on heart: Not all national anthems play out the same - Global Sport Matters

Can anyone sing the national anthem at a baseball game without auditioning? - Quora

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