Through history there have been many secret societies and conspiracy theories about those societies.
This is a list of those who are existing till today.
Bilderberg group
It is the name given to a group of highly influential people who meet ever year in secrecy. The first meeting took place in 1945.
They have continued to meet every year, but the content of their talks has remained a zealously guarded secret.
Trilateral Commission
Group founded by David Rockefeller in July 1973, to get closer cooperation among Western Europe, Japan, and North America. The Commission was repeatedly imputed with desire for taking over the world. That's because most of the USA Presidents after 1973 were members of Trilateral Commission.
Rosicrucians
There are a large number of Rosicrucian groups today. Of the two main divisions, one is a mix of Christianity with Rosicrucian principles, and the other is semi-Masonic. The Rosicrucian in his philosophy marks the divine origin of a man who has fallen through sin, but he has a chance to reunite with God again. It is strongly related to alchemy.
Opus Dei
Opus Dei is an organization of the Catholic Church that emphasizes the Catholic belief that everyone is called to holiness and that ordinary life is a path to sanctity. The celibate numeraries and numerary assistants live in special centers, while associates are celibate members living in their private homes. The order was founded in Spain in 1928 by Roman Catholic priest Josemaría Escrivá with the approval of Pope Pius XII.