Nature - Nature is almost the opposite of technology, as it encompasses that which mankind did not create. I like unaltered nature, but also, gardening, which is how mankind participates and cooperates with nature. Farming is large-scale gardening and today we have many issue with that.
Technology - Mankind's advantage over the animals, our use of and improvement on tools. Technology can take many forms from computers, optics, rockets, cooking pots! I list here the technology in which I have the most interest.
Architecture - Architecture used to be applied only to buildings (a type of system) and the word origin comes from "architect" or "chief builder" in Latin. I am an "Information Technology Architect" so I build (or rather design) systems based on computer technology. Yet, I like building architecture, too, and thus the collection I have here.