Firefighting and Lifesaving
Although neither was ever added officially to the list of Olympic sports, that doesn't mean practitioners have no place at the games. For example, Australian surf lifesavers -- who patrol Australia's extensive beaches as their day job -- have a long history of making strong showings in several associated aquatic sports, including swimming, water polo, kayaking and rowing. They even excel in some track and field events, too.
The firefighting demo events are less well documented, but one must assume some Parisian buildings (hopefully ones constructed for this purpose) were sacrificed in a blaze to see which teams could extinguish them first. In 1900, Portugal took the volunteer division win; a team from Kansas City secured the professional division win.