The book '1001 Ideas That Changed the Way We Think '(2013, Quintessence Editions Ltd) edited by Robert Arp includes nudism as one such idea that originated in 1903 and attributed to Paul Zimmermann.
Here is the extract as reproduced on page 618
1903
Nudism
Paul Zimmermann
A way of life in harmony with nature, expressed through social nudity
It is difficult to pinpoint the origins of nudism or naturism as it is called. However the first official nudist club Freillichtpark (Free Light Park) was opened by Paul Zimmermann in an area of secluded woodland, north of Hamburg, Germany in 1903. It attracted visitors from around the world and nudism gained a large following in Europe, particularly in Germany. The International Naturist Federation was formed in France in 1953 to further the cause.
Nudism was first spoken as a means of improving physical health and lifestyle in the late 1700s, although its precise definition varies from country to country. Nudism encompasses an individual preferring to be naked in his or her home or the militant nudism of public nudity activists. There is also social nudity, nudists who meet together at social events, nudist resorts or beaches and 'nudist colonies', although the term is now somewhat outdated and not used by nudists due to various negative connotations. Cruise lines also offer popular naturist cruises.
Although not as popular as they once were, there are still a number of events in which nudist participate openly on the world stage. The International Naturist Federation has designated the first Sunday in June the World Day of Naturism. Every year in May, everyone - nudists and non-nudists alike - is asked to participate in the World Naked Gardening Day. The World Naked Bike Ride is a clothing optional event that began in 2006 (although many other random cycle rides had occurred prior to that). What began at twenty eight rides in twenty eight cities across the world has mushroomed to more than eighty cities in almost twenty different countries.
Arguments over the pros and cons of public nudity abound, yet surprisingly very little evidence has been forthcoming that the practice has any negative effect on the moral fabric of society.