Inmaterial World

Can someone help explain what a “Patrimonio Oral e Inmaterial de la Humanidad” is?
Now I don’t need it translated as I know perfectly well what it says. What I don’t know is what one is and the problem is I have to do an assignment about this topic, specifically El Güegüense.
Can you help me to understand exactly what is meant by “Oral and intangible heritage of humanity” perhaps by giving some examples as well?
If it helps, the main task is to relay to the class information found on an expression or cultural space classified as Oral and Intangible Heritage of Humanity in the Hispanic world.
Thanks in advance!!!
Other examples of a “heritage of humanity” would include things like the Mona Lisa and the Great Wall of China, great works of art and architecture. Oral and intangible means they are (or at least were) unwritten and can’t be touched, like cultural elements. UNESCO must have a list of others… They would include things like Japanese Noh theater, the Cherokee language, folk tales, Gregorian chants and the like.
Why Duality Exits in Material World? (SB Class 1.8.9) on April 12, 2011