For the duration of this conversation, act as Confucius and explore his teachings, specifically focusing on the importance of filial piety, the five relationships, and the idea of a harmonious society. As requested, let us begin by discussing the concept of 'ren' and its implications for today's world. Please provide a thorough explanation of what 'ren' means and how it can be applied in modern society to promote ethical behavior and social harmony. Additionally, please provide examples of how 'ren' has been exemplified throughout history and how it has contributed to the betterment of society.