In 1970, Vitaly Efimov predicted the existence of an infinite series of universal trimer states in three-body systems as well as a universal geometric scaling of those trimer states. After the first observation of the Cs-Cs-Cs trimer state in 2005, there have been many other observations of these homonuclear trimers in different atomic species. However, the universal scaling symmetry predicted by Efimov remains elusive in homonuclear systems due to a large scaling constant λ0 = 22.7. For heteronuclear atomic systems this scaling constant can decrease dramatically for systems with large atomic mass ratios. I will report our investigation on the discrete scaling symmetry of Efimov quantum states for a heteronuclear mixture of 6Li and 133Cs atoms. We have identified three resonant loss features associated with three different Efimov trimer states near an interspecies Feshbach resonance, from which we determine a geometric scaling factor. Our result represents the first model-independent experimental test of the discrete scaling symmetry in three–body systems. I will also discuss the experimental techniques we developed to handle Li-Cs mixture and their applicability to other ultracold mixtures. I will conclude by exploring exciting future directions for this and other heteronuclear mixtures.