The Illuminati are believed to have been a subversive splinter from Freemasonry, allegedly founded in Bavaria by Adam Weishaupt in the 1700s. Their goal was believed to be to take over Europe (and the rest of the world) and establish a one-world government, while abolishing organized religion. The Illuminati were said to have been officially disbanded in 1785 by the government of Bavaria, and there is little evidence that they have survived into the modern day.
Some conspiracy theorists think the appearance of the eye atop an unfinished pyramid (the so-called "Eye of Providence"), which appears on the back of the US one-dollar bill, means the Founding Fathers were Illuminati operatives or sympathizers. However, amongst them only Benjamin Franklin, John Hancock, John Paul Jones, and George Washington were Freemasons,  and all of them were members of regular Masonic lodges. (Franklin was also a member of the Lunar Society.) Masonic historians also maintain that an unfinished pyramid has never been a Masonic emblem.