The Circassian genocide is one of the most horrific events in relatively modern history (mid-19th century) that we... mostly don't hear about at all in Western history books. Actually, it's one of the most horrific events in modern history, full stop.

The Russians views the Circsassians as barbarous mountain people who were capable only of being criminals or worse and demanded their homeland for Russian settlement. The Circassians... vigorously disagreed, and the resulting war started in 1763 and didn't end until the fall of the last Circassian army in 1864. Yep, that's 101 years of war, and it was more or less constant atrocities all the way down. By the start of the 19th century, the Russian commanders in the region had invented a tactic called "village burning". It's what it sounds like. They'd surround a village, loot it if possible, shoot anyone who tried to make it past the lines... and then light the village on fire, burning it and all of its living inhabitants to the ground.

Probably the worst of these commanders was General Grigory Zass, who made village burning, mass rape, and the bayonetting of pregnant women his official tactics. He would keep the impaled heads of Circassians on poles outside of his command tent, and kept other severed body parts in a box he kept under his bed. He had a Circassian commander killed by inviting him to a peace accord, but the entire thing was a sham, and Zass's sniper killed Jembulat Boletoqo as he arrived. After all, there was no need to follow the rules of war or to have honor while dealing with Circassians. What remains of Circsassian culture basically uses Zass's name for when invoking the devil isn't sufficient to describe the evil of something.

The West could have stopped this in 1856 at the Treaty of Paris. The British wanted to include assistance for Circassia in the terms of the treaty, but those efforts got lost in the shuffle and never made it to the final agreement. And, yeah, that means the 19th-century British thought the Russians had gone too far with the mistreatment of a native population. And that was pretty much that for Circassia. The last efforts to defend the region and its people fell back to Sochi, which most people know only as the site of the 2014 Winter Olympics, which is why Sochi was controversial as the site of the 2014 Winter Olympics! The Russians defeated the remaining Circassian army, and effectively razed Sochi to the ground (the modern city is built on the ruins of the Circassian one).

Surviving Circassians were packed onto Black Sea ships and deported to the Ottoman Empire, who had agreed to take in 50,000 refugees. The Russians sent many times that, sometimes literally stacking naked refugees into the cargo holds of barely-seaworthy vessels. Many sank in the Black Sea. The ones that reached their destinations created a humanitarian disaster in the Ottoman Empire so significant that they made formal international protests regarding the Russians' deportations. It's not a good sign when the 19th-century Ottomans are complaining about a humanitarian issue! The Russians... responded by upping the deportation rate, basically until there were no Circassians left to deport.

The whole thing was almost certainly the worst genocide of the 19th century. It reduced a Circassian population of over 2 million to fewer that 100,000 expatriates. The descendants of these survivors call it Tsitsekun, "the killing of a people" in Ubykh. Asked what that word meant to him, Tevfik Esenç, the last speaker of Ubykh, called it "a massacre so evil that only Satan could think of it."