The Spiral Jetty is a 1,500 foot long, 15 feet wide piece of land art by American sculptor Robert Smithson. It is so large, in-fact, that it can be seen from space as illustrated in the photograph below. So how exactly does such a gargantuan project, requiring massive machinery to move earth get funded, and what economics surround the work? Turns out, the sculpture was financed in part by a $9,000 grant from an art gallery in New York called the Virginia Dawn Gallery, and was eventually donated by Smithson’s wife to the Dia Art Foundation.
https://www.sculpture.org/documents/scmag04/julaug04/spiraljetty/julaug04_spiraljetty.shtml
https://en.wikipedia.org/wiki/Spiral_Jetty