It's the world's most well-known secret society. Rich with symbols and ritual, it's the source of legends ... parodies ... and conspiracy theories. Welcome to the world of Freemasonry. Freemasons laid the cornerstone of America [or] at least some of its most iconic structures, like the National Cathedral in Washington and the Statue of Liberty. So what is Freemasonry? It's the world's oldest and largest fraternity. Its membership is a Who's Who of world history -- George Washington, Benjamin Franklin, Winston Churchill, Mozart, Davy Crockett, Franklin Roosevelt, Harry Houdini, Gerald Ford, Henry Ford, John Wayne, even Colonel Sanders. Freemasonry began in medieval Europe as a guild for stonemasons. The first grand lodge was created in London in 1717. It wasn't long afterward that ... conspiracy theories began. In 1738 Pope Clement XII issued the Catholic Church's first decree against Freemasonry -- and it still applies today. In the U.S., Freemasonry flourished until its secrecy made it the object of suspicion here, spawning America's first third party, the Anti-Masonic Party. Today, Freemasonry has about 1.3 million members in the U.S., down from 4 million in 1959. Among the members today: African-Americans, formerly relegated to a separate, black-only branch of Freemasonry. If you want to be a Mason, you can petition a local lodge for membership. You'll need to demonstrate good character and belief in some sort of Supreme Being. In almost all lodges, it's men only. The House of the Temple for the Supreme Council of the Scottish Rite [is] one branch of Freemasonry. Inside [The House], the temple lodge room is a stunner. And downstairs, you can see the flag that Buzz Aldrin took to the Moon.