Independent since 1776, the United States of America is 241 years old. With the average life expectancy now hovering around 80 years, that means the entire history of the country—from powdered wigs to the Internet of Things—spans a little more than just three back-to-back modern human lifetimes. Historically speaking, America is a young country.

The centenarians who defied the odds and lived to be 100 today could have grandparents who were alive in 1860, provided that both their parents and grandparents gave birth at the age of 30. For a 20 year old whose parents and grandparents both gave birth at the age of 20, their three-generation lineage would date back only to 1960—a full century later.

A lot happened during that century. If someone said “British invasion” at the beginning of it, Redcoats with muskets would likely have come to mind. Just beyond the other end of that timeline, however, the same utterance would have probably sparked a conversation about The Beatles and The Rolling Stones. Chances are good that your actual grandparents were born somewhere in between.

1860

By 1860, the United States was a country that could no longer sidestep a reckoning over the question of slavery. It was an open wound that had been festering since Congress punted on the issue with the Missouri Compromise two generations earlier in 1820.

With the election in 1860 of anti-slavery presidential candidate Abraham Lincoln, South Carolina seceded from the Union. It was the point of no return. War between the North and South was now inevitable.

1870

In 1870, black Americans enjoyed unprecedented optimism under the protection of Reconstruction. That year, the 15th Amendment gave black Americans the right to vote and the first African-American was sworn into Congress. While all that was happening, America’s budding industrial and corporate dominance began to take shape as business titans emerged. John D. Rockefeller founded Standard Oil that year.

1880 

Edison’s invention didn’t stay in Menlo Park for long—electricity quickly began changing the way human beings interacted with each other, with the machines they made, and with the world around them. By 1880, Wabash, Indiana, became the world’s first electrically lighted city.

1890

In 1890, West Point’s football team beat the U.S. Naval Academy’s squad 24-0 in the first-ever Army-Navy game. Also that year, the West filled out some more with the admission of Idaho and Wyoming as states. Nearby, the United States Army massacred hundreds of defeated and starving Lakota Sioux, including their chief, Sitting Bull, at Wounded Knee, South Dakota.

1900

In 1900, the world got a little sweeter when Milton Hershey unveiled his new milk chocolate Hershey’s Bar. That same year, the hamburger was invented and would quickly rise to the top of the American food chain. Also in 1900, America entered the era of the automobile with the first major car show at New York City’s Madison Square Garden—it would soon be a country on the move.

1910

By the start of the 20th century’s second decade, more than 92 million human beings called America home. Also, an American institution known as the Boy Scouts was founded that year.

1915 

By 1915, New York and San Francisco had been connected by telephone, but emerging media technologies weren’t always helpful. That year, D.W. Griffith’s “The Birth of a Nation” freshly demonized black America and breathed new life into the Ku Klux Klan. Overseas, Ottoman Turks used the cover of war to slaughter more than a million Armenian civilians in the century’s first genocide. It would not be the last.

1919

In 1919, a movement built on a century of activism that involved groups as disparate as abolitionists, women’s rights organizations, and religious revivalists got its due. The 18th Amendment became the law of the land, and Prohibition ended the manufacture, sale, and consumption of alcohol in America—at least on paper. In reality, Prohibition drove booze underground, creating a gargantuan black market that fueled an unprecedented rise in organized crime.

1920

The 1920 census was the first in history to require nine digits to record—America was now more than 100 million people strong. About half of those people were women, and now, thanks to the 19th Amendment, they were finally granted the right to participate in American democracy. Women’s suffrage succeeded a full half century after black men were afforded the right to vote—in policy if not in practice—when the 13th Amendment was ratified during Reconstruction.

1930

In 1930, the country was sinking into a financial depression, but life went on. An American astronomer discovered Pluto, and a man with the last name Birdseye invented the process that made frozen food possible. It was also the year that a seed was planted to eventually grow into the digital age: Vannevar Bush invented the analog computer at Massachusetts Institute of Technology.

1940 

In 1940, Hitler’s war of military conquest and civilian annihilation were raging in full force. Paris fell to the Nazis that year, and the first captives began arriving at the Auschwitz concentration camp. In response, Roosevelt began conscripting troops and expanding the Navy.

1950 

After what seemed like a brief peace, America was once again at war in 1950, this time in Korea. Any hope for a quick resolution ended when communist Chinese troops poured over the 38th parallel in support of Soviet-backed North Korean troops. That same year, America sent 35 advisors to support anti-communist forces in a remote and obscure Southeast Asian country called Vietnam.

1960

In 1960, the youngest American grandparents were born into a decade that would be remembered as among the most turbulent in American history. Social upheaval, a gruesome war, African-Americans struggling for civil rights against groups like the Ku Klux Klan, and a presidential assassination would define the decade—just as it had a century before.