1950s: Elizabeth II is crowned queen of England, and Winston Churchill, Anthony Eden, and Harold MacMillan, consecutively, are elected prime minister.

Today: Elizabeth II continues as queen of England. Her reign has outlasted ten prime ministers, with Tony Blair serving in the post in the early twenty-first century.

1950s: Existentialism, as espoused by Søren Kierkegaard and Martin Heidegger, is developed in France by Jean-Paul Sartre through his essays and novels.

Today: Jacques Derrida, a Frenchman whose philosophical essays have inspired and influenced literary criticism all over the world, espouses deconstruction and postmodern theories.

1950s: Forgetfulness in old age is often referred to as a natural state of aging. Generic terms such as dementia or senility are applied to older people who display these symptoms.

Today: After many years of research, Alois Alzheimer's theories have been accepted, and doctors and researchers have come...