potomac.gorge.earth.day-20190422-0002 April 22, 2019 at 1080 × 721 in potomac.gorge.earth.day-20190422-0002 ← Previous Next → A great blue heron stalks the shallows of one of the locks along the C&O Canal. Overhead photograph of great blue heron as it stalks the shallows in one of the locks along the C&O Canal in Maryland.