AVE6320536: 1950s: Toddler picks up ball outside / Bridgeman Images

AVE6320539: 1950s: Toddler hits newspaper and Father talks angrily / Bridgeman Images

AVE6320558: United States, 1960s: fast animation of heart pumping blood / Bridgeman Images

AVE6320560: United States, 1960s: arrows show blood flow through vessels of heart / Bridgeman Images

AVE6320564: United States, 1960s: animation of cells in human body / Bridgeman Images

AVE6320569: 1950s: Boy sits on step alone watching boys bike away / Bridgeman Images

AVE6320572: 1950s: Boy helps put baby powder on baby / Bridgeman Images

AVE6320735: United States, 1950s: Farm equipment in field / Bridgeman Images

AVE6320741: United States, 1950s: Prisoners in train car, men close car / Bridgeman Images

AVE6320742: United States, 1950s: Army marches in Red Square / Bridgeman Images

AVE6320755: United States, 1950s: Soldiers fire gun / Bridgeman Images

AVE6320756: United States, 1950s: Sailors wave from ship, pan to sign on side of ship / Bridgeman Images

AVE6320759: United States, 1950s: Sailors train with ship gun / Bridgeman Images

AVE6320765: 1970s: Model of human brain flashes on black background / Bridgeman Images

AVE6320771: 1970s: Woman and girl at table / Bridgeman Images

AVE6320778: 1970s: Section of brain viewed through microscope / Bridgeman Images

AVE6320780: 1970s: Water with foggy horizon / Bridgeman Images

AVE6320790: 1970s: Squid swim around tank of water / Bridgeman Images

AVE6320793: 1970s: Drop of liquid falls from thing string / Bridgeman Images

AVE6320797: 1970s: Man looks down / Bridgeman Images

AVE6320798: 1970s: Flashes of light illuminate monkey in restraints / Bridgeman Images

AVE6320799: 1970s: Man stands / Bridgeman Images

AVE6320801: 1970s: Man sits / Bridgeman Images

AVE6320809: 1970s: Woman looks into isolette / Bridgeman Images

AVE6320811: 1970s: Hands hold premature baby in isolette / Bridgeman Images

AVE6320821: 1970s: Man leans down / Bridgeman Images

AVE6320826: 1970s: Boy smiles / Bridgeman Images

AVE6320833: 1950s: Man in suit and hands walks down nighttime sidewalk with hands in pockets / Bridgeman Images

AVE6320834: 1950s: Man stops in front of house and gestures at entrance / Bridgeman Images

AVE6320836: 1960s: Man sings in front of microphone while holding sheet music / Bridgeman Images

AVE6320840: 1950s: Girl wakes up in oversized, cartoon version of the study / Bridgeman Images

AVE6320847: 1950s: Little girl stands on oversized book / Bridgeman Images

AVE6320850: 1960s: Young women thumb through records in record store / Bridgeman Images

AVE6320856: 1960s: Woman coat sings as band plays behind her / Bridgeman Images

AVE6320857: 1960s: Man with headphones sits in booth and listens to band play through glass window / Bridgeman Images

AVE6320863: 1960s: View of city from hill / Bridgeman Images