What is heritage? Webster's defines it as "property that is or can be inherited; something handed down from one's ancestors or the past; a characteristic, culture, or tradition." In its broadest sense, it would seem that heritage can include virtually everything we receive from our predecessors -- even those things that we consider as bad or negative. Pollution, for example, could be a part of our heritage according to this definition.
In practice, heritage usually denotes those traditions and characteristics that we consider worthy of preservation. In other words, we most often apply the term to the things that we have inherited that we consider most special or representative of our past, and that we wish to pass on to posterity. Even in this sense, however, the term is extremely broad. It can apply to the tangible (architecture or the natural environment, for example); or to the intangible (history, culture, popular values, and so on). Heritage can be a house, an historic event, a tree, a species of animal, a landscape, a park, a mountain, a folk tale, a belief, a tradition, a song, a style of dress...
Our challenge is to determine what constitutes our heritage, and what aspects of it we wish to pass on. Each generation in every society must face this task.