Riders negotiate a dune as they compete in the Adult Solo race at the HydroGarden Weston Beach Race in Weston- super- Mare, south west England, on October 9, 2016. Beach racing is an offshoot of enduro and motocross racing. Riders on solo motorcycles and quad bikes compete on a course marked out on a beach, with man- made jumps and sand dunes being constructed to make the course tougher. (Photo by Adrian Dennis/AFP Photo)

A dog jumps into water during the “World Dog Show” in Leipzig, Germany, November 10, 2017. Around 31,000 animals are expected at the international pedigree dog competition taking place from 8 to 12 November 2017. (Photo by Hannibal Hanschke/Reuters)

Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)

Participants of the so called “Victorian Picnic” walk in fancy costumes during the Wave Gothic Festival (WGT) in Leipzig, Germany, Friday, June 2, 2017. Approximately 20,000 goths and other dark subculture fans such as cybergoths, metalheads, steampunks, neo- Victorians, dark romantics, dark electro, industrial, medieval and fetish fans are expected to attend the world' s largest gothic and “dark” culture festival until June 5, 2017. (Photo by Tobias Schwarz/AFP Photo)

Athletes vie for the ball during the Mud Olympics in Brunsbuettel, Germany, 30 July 2016. Since 2004, amateur athletes have been competing in various events at the mouth of the Elbe river on the North Sea. The proceeds are traditionally donated to the Schleswig-Holstein Cancer Society. (Photo by Daniel Bockwoldt/EPA)

Tree trunks are seen in a forest on November 8, 2011 near Landau an der Isar, Germany. The German government is conducting a nationwide project to estimate the number, variety and geographic distribution of trees and forests in Germany, as well as their condition and health. Approximately a third of Germany is covered in woodlands, and though that territory has actually expanded since 1989, some analysts fear demand for wood will outstrip supply in coming years due to national growth in industry and bio-energy needs. (Photo by Johannes Simon/Getty Images)

A house and garden is illuminated ahead of Christmas in Olching near Munich December 11, 2014. The house is decorated with more than 30,000 lights. Every year hundreds of houses across Germany are decorated by their owners with lights ahead of Christmas. (Photo by Michaela Rehle/Reuters)

A participant competes in the “Nostalgic Ski Race” in the western town of Neuastenberg February 8, 2015. The “Nostalgic Ski Race” is held every two years with about 40 participants and is organized by the ski club of Neuastenberg, a town which was founded in 1713. The conditions for the participation in the race are vintage skis and dresses. (Photo by Ina Fassbender/Reuters)