Popularly called "the Wheel of Samsara," the Bhavachakra is one of the most important symbols in Buddhism, being an illustration of everything that exists and how existence functions. While the superficial, public-level meanings are fairly well-known (such as the three poisons, the twelve nidanas, the six realms), few know that the actual purpose of the symbol is very deep, revealing the inner workings of our mind, and thereby illustrates the source of suffering (samsara) or liberation from suffering (nirvana).
The lectures are also playing continuously on Gnostic Radio:
"The one who does not know how to fulfill his duties as a simple citizen cannot tread the path of the great mysteries. Many disciples forget the good manners of a sincere and honorable gentleman or lady and become truly irresponsible and even dangerous individuals."