The didgeridoo is an Australian instrument. It is made from eucalyptus tress hollowed out from termites. The didge is played by using a technique called circular breathing. Circular breathing is when you breathe into your nose and out of your mouth at the same time. It is much harder than expected but those able to master circular breathing can master the didge. The vibrations of the players lips and breath cause the air inside of the instrument to vibrate at different frequencies. When the frequency of the air matches the natural frequency of the air column it resonates. When the frequency's resonate it creates that big sound that you hear. The didges irregular shapes make its natural frequency very different from other wind instruments and make the didge quite unique.