Stock photography, photos: Mississippi River Lock and Dam #1 Stock photos of Mississippi River Lock and Dam number one, Minneapolis, Minnesota, seen at night thru the historic Stone Arch Bridge. This is the downstream side of the lock; the large doors are more than fifty feet tall. After the creation of the Patriot Act, photography of critical infrastructure such as this is, often strongly, discouraged. Photograph: © Michael Gilday Click for a larger image and more information Keywords associated with this stock photo: lock and dam, mississippi river, boating, shipping, nighttime, night, river, water, corps of engineers, army, government, critical infrastructure, terror, terrorism target