Since 2000 activists round the 'Wald-Fkk'-movement ('Free Range Nudism' - being nakie everywhere in nature) organize a naked bike tour south of Karlsruhe /river Rhine once a year.
The tour is directing 35 - 40 kilometers through wood, plain fields, touches a lake, leeds through the floodlands of river Rhine and the southern suburbs of Karlsruhe - all completely nakie ! :)
There are several rests with bathing oppertunity.
As far as possible a naked walk in the wilderness of wetlands at River Rhine will be integrated.
This ride is suitable for everyone, who is just able to hold in saddle, especially for our ladys.
There are absolutely no altitudinal obstacles blocking the nude route.
The joint demonstration of the naked cycling idea has major count here.
(section of wald-fkk.de)
How the 10th edition was:
Nacktradtour Karlsruhe 2009 (report and horny pics in german)
About history of the annual Karlsruhe naked bike tour there comes this Wikipedia wiki page (international/english) :