2015 is turning into a year of anniversaries. Admittedly accidents of the calendar and the profit motive of publishers has something to do with these observances, but in an era of the eternal now, a little historical perspective occasionally can’t hurt.

Today, in case you haven’t gotten the memo is the 200th anniversary of the Battle of Waterloo. I know, who cares? But it may be worth recalling that Napoleon, like Charlemagne and the Caesars before him, aspired to a unified, rationalized Europe – albeit ruled by him.

Some parts of his program were admirably visionary, modernizing the legal system and so forth, but his method was very traditional – to lay waste, subjugate conquered people, force them to live by his rules and leave a lot of dead bodies in his wake. Forty thousand fell at Waterloo on a Sunday two hundred years ago.

As usual, there were large unintended consequences. The vacuum created by the collapse of French power after Napoleon fueled the rise of Germany and helped make it the dominant continental power for the last 100 years, frequently emulating the Napoleonic taste for conquest with unfortunate results. Indeed, the most unfortunate fact about historical anniversaries is that those celebrated most often tend to involve catastrophes, especially the fall of tyrants after they have caused vast misery.

So far, if anyone’s been keeping score, we’ve had the 70th anniversary of VE Day in May and are fast approaching the 7oth anniversary of Hiroshima and V-J Day. These remembrance are too often triumphal. They really should be viewed as cautionary tales.

Earlier this year we marked the sesquicentennial of Appomattox, the end of the worst cataclysm this country has ever endured, followed a few days later by the 150th anniversary of the assassination of Lincoln. He was the first, but far from the last, of our presidents to be killed on the job. Fifteen percent of all presidents have been shot, and there have been attempts on the lives of 25 percent.

The watershed year of 1865, 150 years ago, also saw the passage of the 13th amendment abolishing slavery, but we have all been reminded by the movie “Selma” that one hundred years later, in 1965, the struggle to obtain equal rights still continued, as it does to the present day. Some things never change, human wickedness chief among them.

Perhaps we should have solemn celebrations of happier anniversaries to balance out the equation. One hundred years ago in 1915 the cataclysm of World War I was in full cry. At second Ypres, poison gas was first used and you could hear, as Wilfred Owen wrote, “the blood come gargling from the froth-corrupted lungs.” There were 100,000 casualties at Ypres, at Gallipoli 500,000. The Lusitania was sunk, Zeppelin attacks in London pioneered the bombing of civilians.

But no era is entirely the worst of times. In 1915, Ford sold its millionth car and introduced the gas-propelled farm tractor. Margaret Sanger published a guide to family planning, though she was jailed for doing so. The first transcontinental phone call was made, and Charles Chaplin’s film, “The Tramp” appeared. As its author later wrote, “Smile though your heart is aching.”

The same year as the Lincoln assassination, Mendel formulated the law of heredity, the transatlantic cable was laid, MIT was founded, the first oil pipeline built in Pennsylvania and the modern world with all its promise and peril was aborning.

Eight hundred years ago this week, in an English field angry barons compelled a king to accept a check on his power and Magna Carta was signed. It took centuries, but slowly the notion caught on that all men, not just barons, ought to be protected from arbitrary power, an idea that animated a revolt against another king 240 years ago this April at Lexington and Concord. As E.M. Forster once wittily said, “Two Cheers for Democracy.”

And last, but far from least, 400 years ago in 1615, Galileo first ran afoul of the Catholic Church for professing science that clashed with dogmatic superstition. He was eventually subjected to the inquisitors, found heretical, forced to recant, and lived out his censored days under house arrest. But the church couldn’t kill the truth he discovered. The universe behaved as he had concluded, though it wasn’t until 1992 that Pope John Paul II conceded Galileo might have had a point.