AVE6322047: United States, 1950s: View of crowd at circus, Firestone factory in background / Bridgeman Images

AVE6322126: 1940s: Hands gaff and pull large fish into boat / Bridgeman Images

AVE6322305: United States, 1960s: man work in supermarket / Bridgeman Images

AVE6322330: United States, 1960s: lady looks at bag on counter / Bridgeman Images

AVE6322333: United States, 1960s: Lady at check out greets customer / Bridgeman Images

AVE6322342: 1950s: Abandoned schoolhouse / Bridgeman Images

AVE6322372: 1920s: Fun Factory titles card with illustration of cops and men in a car / Bridgeman Images

AVE6322381: 1920s: police car explodes in a puff of smoke / Bridgeman Images

AVE6322450: United States, 1970s: Young man scrubs graffiti off of bathroom stall under supervision, another young man talks to the camera, young man stops another young man from painting graffiti on a wall, a young woman talks to the camera, an older woman talks to the camera / Bridgeman Images

AVE6322477: United States, 1980s:computer model shows impacts of gravity on human brain / Bridgeman Images

AVE6322480: United States, 1950s: View of oscilloscope, zoom in, hand turns knob, lights dim / Bridgeman Images

AVE6322356: United States, 1960s: lady stacks groceries on conveyor belt / Bridgeman Images

AVE6322362: 1950s: Meeting / Bridgeman Images

AVE6322377: 1920s: large fat man squeezes into desk chair in classroom with boys and girls / Bridgeman Images

AVE6322380: 1950s: Children walk through lunch line / Bridgeman Images

AVE6322467: United States, 1980s:researchers put biological experiments together on earth before space mission leaves / Bridgeman Images

AVE6322488: United States, 1950s: Animation of sound waves hitting ear drum / Bridgeman Images

AVE6322491: United States, 1950s: Animation of sound waves inside ear / Bridgeman Images

AVE6322494: United States, 1950s: Animation of sound waves inside ear / Bridgeman Images

AVE6322518: United States, 1980s:cells grow on agar gel / Bridgeman Images

AVE6322800: A boy walks up a set of stairs, another boy bikes up a steep hill / Bridgeman Images

AVE6321423: United States, 1940s: Quarter pound bricks of butter being wrapped by an automated machine / Bridgeman Images

AVE6321462: United States, 1940s: Aerial views of destroyed buildings / Bridgeman Images

AVE6321480: United States, 1940s: Dwight D Eisenhower waves from car in parade / Bridgeman Images

AVE6321489: United States, 1940s: A factory worker removes a pipe from a large machine with a wrench and places it into a steel basin, then removes the pipe from the basin and slides in over a smaller pipe / Bridgeman Images

AVE6321525: Kaiser of Germany Stag Hunting / Bridgeman Images

AVE6321556: United States, 1970s: Interior of closet, boy opens door and removes box / Bridgeman Images

AVE6321568: United States, 1970s: Close up, boy's hands stack Lego pieces / Bridgeman Images

AVE6321574: United States, 1970s: View of 'Don't Walk' sign / Bridgeman Images

AVE6321586: United States, 1970s: Close up, child's hands put Lego structure on board, zoom out, hands spin structure / Bridgeman Images

AVE6321595: United States, 1970s: Child's hand plugs wire into Lego battery box / Bridgeman Images

AVE6321625: United States, c.1950: Children duck on sidewalk, against brick wall, covering heads with jacket collars and hands, pan shows adult woman ducking in alcove / Bridgeman Images

AVE6321637: United States, c.1950: Elementary school students eat lunch at tables, a student practices ducking and covering under a lunch table while other students look on, an older student directs the other students' attention to the boy's technique / Bridgeman Images

AVE6321643: 1980s: Chrysler Corporation logo / Bridgeman Images

AVE6321646: 1980s: Text on screen / Bridgeman Images

AVE6321664: United States, 1940s: Man on porch swats at mosquitoes / Bridgeman Images