“The most shocking fact about war is that its victims and its instruments are individual human beings,” wrote Aldous Huxley in an essay called “Words and Behaviour,” published in 1936, “and that these individual beings are condemned by the monstrous conventions of politics to murder or be murdered in quarrels not their own….”

That’s a sobering reminder that each casualty of war is not just a statistic but an actual human being. Whether a soldier or a civilian, every metric represents a life interrupted by a conflict most had no hand in creating. 

As the world watches the current war in the Ukraine unfold daily in headlines and news broadcasts, ghosts from battles fought not so long ago still loom on the edges of the public consciousness. Wars aren’t just material for the history books. Some of the worst atrocities happened in the modern era. 

World War II ranks as the deadliest conflict in history. While an exact number is hard to pin down, some estimates have estimated total military and civilian deaths as up to 80 million, with millions more wounded, captured, or otherwise displaced. (These are the deadliest battles in U.S. history.) 

The First World War, which had its own share of deadly battles and massive destruction. Over 9 million soldiers died, with another 21 million more wounded. Civilian casualties reached close to 10 million. 

24/7 Tempo has compiled a list of the deadliest battles of the modern era, based on sources, such as History.com, War History Online, the Imperial War Museum’s website, Britannica and World Atlas. While most of these battles occurred during the two world wars, the Vietnam War, Sino-Japanese War, and Chinese Civil War are included. 

Click here to see the most devastating battles in recent history

In some cases, individual battles were included as part of larger engagements – for instance, the Battle of Kiev as part of Operation Barbarossa. Note that “casualties” doesn’t necessarily mean deaths; the term encompasses not only those killed in battle but also the wounded, the missing, and prisoners of war. (These are the wars in which the most Americans died.)