Oil Painting with view of Hawthrone Bridge from 8th floor of a parking structure. The Hawthorne Bridge is a truss bridge with a vertical lift that spans the Willamette River. It is the oldest vertical lift bridge in operation in the United States. It is also the busiest bridge in Oregon, with over 4,800 cyclists and 750 TriMet buses daily. Plein-Air Oil Painting with jewel like impressionist painting strokes . En plein air is a French expression which means “in the open air” and is used to describe the act of painting outdoors in natural light. Light and wondrous nature are the master teacher for this artist and her creations.