Opus 40 is a huge environmental dry stone sculpture built by one man, Harvey Fite. It is described in this video as "one of the greatest (and) most remarkable pieces of art.....an elegant...artistic triumph".
As to the question - What is Art? it is almost impossible to give a concise definition. It would be even more difficult to have a consensus as to what should and should not be included as definitive examples of true 'art'.
Opus 40 provides a setting for performance art of various kinds, as well as poetry readings and the displaying of works of art and sculpture. As such it represents for me the diversity of dry stone artistry as it encompasses 'what art is' on a larger scale,
The art of dry stone doesn't have to be just the end product, it's often not just the finished work, it is the work - the event. As a structural dance of suspended choreography it can have many forms. These forms evolve and in some cases, as seen in this video, they even bring artists and craftsmen-and-women back together to be creatively restored.
The art of building with dry stone is fundamentally the process of adaption and improvisation. What better way to celebrate this fact than holding a jazz concert within the artistic setting of Opus 40.