I would like to start with a brief news item in the August 1999 issue of National Geographic which gives some food for thought: "With 5,000 climbing routes, such as Double Dogleg and Walk on the Wild Side, California's Joshua Tree National Park attracts about 140,000 enthusiasts a year to test their skill on granite boulders. But some visitors view their metal bolts as defacements hammered into rocks.
The Regional Park of the Po River Delta was set up in 1988 (it belongs to a Consortium of Public Bodies). It extends over 54,000 hectares of land and stretches across 45 km of the Italian Eastern coastline (45 km of the more than 90 km that go between the provinces of Ferrara and Ravenna) and is one of the largest and most significant natural parks in Italy.