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On April 18, 1906, a devastating magnitude-7.9 earthquake destroyed much of San Francisco, California, killing more than 3,000 people and leaving 225,000 homeless. Fires started by the quake burned for three days and destroyed 80% of the city. The rebuilding of San Francisco in under a decade was one of the greatest urban reconstruction efforts in American history.

On April 18, 1980, Zimbabwe gained independence from the United Kingdom, ending the white-minority regime of Rhodesia and the guerrilla war that had lasted 15 years. Robert Mugabe, leader of ZANU-PF, was elected Prime Minister and later President, governing with increasing authoritarianism until forced to resign in 2017. Zimbabwe began as the "jewel" of the African continent.

On April 18, 1955, physicist Albert Einstein died at Princeton Hospital, New Jersey, at age 76. He refused another operation for the aneurysm he suffered, saying he had lived long enough. Against his wishes, the coroner removed his brain, which was studied by scientists for decades seeking the secret of his intelligence. His ashes were scattered at a secret location.