For roughly the first half of the past fifty million years, the region lay beneath a warm, shallow sea.

NEWYORKER: Bones of Contention

For the first time in fifty years my country is preparing for war.

BBC: Is the UK government right to deploy British troops?

For the first time in more than fifty years, Cuban citizens can travel abroad without permission from their government.

FORBES: It's Time For The U.S. To End Its Senseless Embargo Of Cuba

It was fifty years since the first live pictures from America were broadcast to Europe, via Telstar 1, the first communications satellite to relay a television signal.

FORBES: Telstar, the Fifty Year Old Hero of Communication

Then it might be the white-shoe Wall Street establishment of fifty years ago against the embodiment of twenty-first-century post-ethnic America.

NEWYORKER: Money Pol

Fifty years later, the first children's book of American origin issued from Boston.

NPR: Excerpt: 'Minders of Make-Believe'

And though Tony was in good shape for his age, I was a little put out the first time to see what fifty-four years could do to a body.

NEWYORKER: Hand on the Shoulder

Its opening phase appears to have started about fifty thousand years ago, when the first humans migrated across Australia and America.

NEWYORKER: The Sixth Extinction?

Fifty years from the date of his first breakthrough study of tobacco, Sir Richard was able to enjoy the fruits of a lifetime of groundbreaking work.

BBC: NEWS | UK | Lung cancer scientist dies at 92

Fifty years after the contraceptive pill was first licensed in America and 37 years after the Supreme Court legalised abortion, women seem to agonise more than ever about breeding.

ECONOMIST: The tyranny of choice

Now in fairness to President Obama, almost every president for the past fifty years has fallen in the polls after the first half of his term.

FORBES: Obama and the High Cost of High Expectations