A map requested by Jeckl.
This is based on the timeline "Decades of Darkness" by Jared over at Alternate History.com [link]
I shan't go into too much detail, since it isn't my timeline, but it is a world in which a War of 1812 Gone Wrong leads to New England breaking away from the US (later followed by some other bits) and the remaining USA, being numerically dominated by slave states, follows a path of large-scale slave-holding and aggressive territorial expansion, eventually moving into Latin America and either fully enslaving or enserfing the duskier-hued inhabitants.
As the result of butterflies, a big-ass Germany forms earlier than in our world, and after a couple wars the Germans end up dominating Europe, the Russians most of the stuff to the east, and the USA/King size Confederacy dominates the Americas, as here [link]
An era of "three superpowers" begins, with the Brits reduced to a rump empire in exile and the French have their country broken up. This is a variant version in which not everything goes the USA's way, and things don't go well at all for the Germans.
The Halifax Powers win the North American war, the US losing some border territory and most of its Caribbean holdings. Later, with a weakened USA and the Russians on side, the British-French-etc alliance wins the later Great War. Russia didn't do quite as well as in the original scenario in Asia, but made up for it by extracting an extremely high price for entering into the war on the non-German side: pretty much all of Eastern Europe is in Russia's pocket.
The USA was able to hold its own on the American continent, although it has to pull back from hard-to-access southern Brazil in the face of well-equipped Latin troops and military threats from the North. Currently it is slowly but surely crushing the various Montevideo League-backed rebellions in the territories and plotting revenge.
Germany has been divided. This is probably not maintainable in the long run, and France's extension to the Rhine was probably not a good idea either (the local Germans are Not Happy), as Napoleonically Glorious as it was. The five allied powers (the UK, France, Japan, New England, and a united Italy), currently hang together for fear of hanging separately, knowing that none of them individually is strong enough to stand up to Russia or the US. The Nightmare Scenario, of course, is Russia and the US joining forces.
However, even as people in Canada and New England peer nervously southwards, and those in Japan nervously westwards (the French are fairly relaxed, because they're confident the Russians aren't going to want to take on the headaches of keeping the Germans disunited, and the USA is on the other side of an ocean), something is going on in labs and university campuses and government research centers. Something big. And depending on who gets ahead in this so far largely unseen race, the entire balance of power could be utterly upset...