Weather vanes: US exhibit looks at artworks with a purpose

"Dove Of Peace" is loaned by the Mount Vernon Ladies Association to the American Folk Art Museum for an exhibit on weather vanes. It was commissioned by George Washington, an amateur meteorologist. He asked Mount Vernon's architect, Joseph Rakestraw, to design the dove-shaped weather vane with olive branches in its mouth. Photo: AP

Perched atop churches, barns, businesses, homes and seats of government, weather vanes have over hundreds of years taken the form of everything from farm animals to pets, storybook figures to race cars.

They were invented for one important job: telling which way the wind was blowing. Gradually, they became appreciated as an art form.