Illuminati

The Illuminati is a secret society of powerful men whose origins date back several hundred years. Through subtlety, the Illuminati attempts to dominate the world by controlling present day governments, corporations, organized religion, and even the global economy.

The Illuminati was started in 11th century Persia by Hasan Y. Sabah. Sabah erected a mountain fortress where he trained a private guild of assassins that he called the Hashishin. At the time of the Crusades, Sabah's occult lore came into the hands of European soldiers, particularly the Knights Templar. What they learned from Sabah and the Hashishin is unknown, but it was at this time that the Templar Knights became obsessed with a mystical artifact known as the Holy Grail (dogmatically, the cup that Christ drank from at the Last Supper, and that which caught his blood during the crucifixion).

Over the course of several hundred years, the Knights Templar evolved into a stronger secret society known as the Order of the Rosy Cross (the Rosicrucians). The Rosicrucians built upon the work of their predecessors and became notorious for their skills at alchemy. They also indoctrinated new members into their order by way of ritual, all of whom were sworn to take a sacred oath of secrecy.

One of the Illuminati's most recognizable figures is the immortal Vandal Savage. Having lived literally thousands of years, Savage is the guiding force behind most of the Illuminati's activities.

Skull and Bones is a secret society at Yale University in New Haven, Connecticut. It is a branch of the Illuminati. This is just conjecture based upon famous conspiracy theories.

Referenced
Superfriends
 * Season 6: The Fear