Aviation archaeology is a recognized sub-discipline within archaeology and underwater archaeology as a whole. It is an activity practiced by both enthusiasts and academics in pursuit of finding, documenting, recovering, and preserving sites important in aviation history. For the most part, these sites are aircraft wrecks and crash sites, but also include structures and facilities related to aviation. It is also known in some circles and depending on the perspective of those involved as aircraft archaeology or aerospace archaeology and has also been described variously as crash hunting, underwater aircraft recovery, wreck chasing, or wreckology .