GLP Celebrates 25th Anniversary Features by Thomas Richard - June 11, 2019 Attendees joining GLP’s 25th Anniversary celebrations at PL+S Frankfurt GLP started out near the famed Black Forest. A mountainous region in southwest Germany, bordering France. Known for its dense, evergreen forests and picturesque villages, it is often associated with the Brothers Grimm fairy tales. However unlike the fairy tales, GLP’s growth