My favorite series of work is from an artist named Mara Haseltine. There are many examples of her work on her website, I am going to link to the whole page. I like Water-Molecule Dream Catcher, http://www.calamara.com/dream_catch.html. To build this water molecule, she collected trash flowing in the Potomac River in a 3 hour time span. Her wider message was, water connects all of life, all these pieces of trash used to build the water molecule came from the Potomac River, which connects to the ocean, and on and on.
Another one of her works is called Waltz of the Polypeptide. It is a large scale sculpture, in with the view can literally walk through the birth of a single protein.