Once confined to the internet's fringes, the extremist movement has been emboldened by the rise of Donald Trump. Here's everything you need to know:

What is the alt-right?
It's a weird mix of old-school neo-Nazis, conspiracy theorists, anti-globalists, and young right-wing internet trolls — all united in the belief that white male identity is under attack by multicultural, "politically correct" forces. Alt-righters are primarily active online, where they taunt progressive and mainstream conservative opponents with anti-Semitic, misogynistic, or racist emails, tweets, and other social media posts, and exchange white-nationalist memes and conspiracy theories on anonymous forums like Reddit and 4chan. Another major alt-right platform is Breitbart.com, a right-wing news site that was given a major boost when Breitbart head Stephen Bannon was named CEO of Donald Trump's Republican presidential campaign in August. As a result, the alt-right has become "the most important pushback against having a multicultural and pluralistic society since the 1920s Klan," says investigative journalist Chip Berlet, who studies extreme right-wing movements.

Where did the movement originate?
The term "alternative right" was apparently coined in 2008 by Duke-educated historian Richard Spencer to describe right-wingers who feel "deeply alienated, intellectually, even emotionally and spiritually, from American conservatism." Among this alternative-right fringe, there was a growing sense that America had been abandoned by weak and feckless "cuckservatives" — conservatives who had been "cuckolded" or emasculated by their failure to fight diversity, globalization, and immigration. Spencer founded a new online publication called Alternative Right, filled with pseudo-scientific essays on race and genetics, with titles like "Is Black Genocide Right?" That intellectual tone disappeared as a younger breed of meme-posting right-wingers took over the movement, which they rebranded the more internet-friendly "alt-right." Fifty years ago, "these people were burning crosses," says Jonathan Greenblatt of the Anti-Defamation League. "Today they're burning up Twitter."

Who are today's alt-righters?
The movement's leading provocateur, Milo Yiannopoulos (see below), defines the alt-right as a "young, rebellious contingent who feel a mischievous urge to blaspheme, break all the rules, and say the unsayable." Alt-righters have their own lexicon — "libtards" for liberals and "cucks" for mainstream conservatives, to name two of the least offensive terms — and their own imagery. One of the most-used memes is Pepe the frog, a once popular millennial cartoon reclaimed by white supremacists on 4chan. Pepe is regularly posted wearing Nazi insignia or even depicted as Trump himself. Trump's eldest son, Donald Trump Jr., recently posted a Pepe image; he later claimed he had no idea it was associated with white supremacy. Another signature alt-right trick is to use "echoes," or triple parentheses, around a person's name when mocking him or her online — a signal to fellow anti-Semites that the person is Jewish.

What about Breitbart?
The site is the unofficial media hub for the alt-right, and home to Yiannopoulos himself. Typical posts include "Big gay hate machine closes Christian pizza parlor" and "Birth control makes women unattractive and crazy." Breitbart's beating heart is Stephen Bannon, a former Goldman Sachs banker who has made it his personal mission to "professionalize" the wildest, angriest fringes of the alt-right. Bannon — whose ex-wife accused him of domestic violence and anti-Semitic comments — has been behind the alt-right's most sensational campaigns. "If there's an explosion or a fire somewhere," says Matthew Boyle, Breitbart's Washington political editor, "Steve's probably nearby with some matches."

How does Trump fit in?
Trump began his national political career as the leading champion of birtherism — the belief that President Obama was born abroad and is therefore an illegitimate president. This has long been one of the alt-right's favorite conspiracy theories. Since Trump announced his presidential run last year, he has been the alt-right's candidate of choice — both for his outrageous, say-anything tone, and for his nativist proposals to ban Muslim immigrants and deport Mexicans. "[Trump's] fighting for us. He's saying we're going to be great again," says Spencer, the founder of the alternative right. "He's done more to awaken that nationalism than anyone in my lifetime. I love him."

Is the alt-right here to stay?
Even if Trump loses in November, the movement could continue to be a powerful political force. Bannon and Trump's rumored backup scheme is to launch a provocative alt-right media empire that will capitalize on Trump's popularity and compete with Fox News. There's also the wider fear that the alt-right's emergence into mainstream political discourse — accompanied by white supremacist, racist, and misogynist ideas and language — may have prompted a broader cultural shift in America. "Something happened in 2015 with the emergence of Trump.... Something was let loose by him," says conservative commentator John Podhoretz. "This code language — 'It's time to stop being politically correct' — is something he never defines. It's liberating, but there's no limiting factor. Somehow he has let loose this dark force."

The alt-right's enfant terrible
One of the most famous figureheads of the alt-right is self-styled provocateur Milo Yianno­poulos, or just Milo — a bleached-blond gay Brit who rails against feminism, Islam, and the "guilt-­mongerers" of the progressive left. Milo has declared his birthday as World Patri­archy Day, and set up an educational "charity" for white men called the Yianno­pou­los Privilege Grant. In his mission to provoke outrage, Milo has formed some unnatural alliances. At this year's Republican National Convention, he and anti-Islam conservatives held a "Gays for Trump" party, which Milo attended wearing a bulletproof vest and a tank top with a rainbow fist holding a gun and the caption "We shoot back." And while Milo has spoken openly about his erotic attraction to "tall black men," his followers include some of the most extreme white supremacist voices on the alt-right. In July, he was banned by Twitter after launching a racist trolling campaign against black comedian Leslie Jones. Milo's shock humor has a dark side, says Heidi Beirich from the Southern Poverty Law Center, which tracks hate groups. "It's like he's joking: 'Ha ha, let me popularize the worst ideas that ever existed.' That's new, and that's scary."