Models promote the game “Diamond Dogs” during the Gamescom 2015 fair in Cologne, Germany August 5, 2015. Hundreds of thousands of visitors will enjoy one of the world's largest computer and video game events until Sunday. (Photo by Kai Pfaffenbach/Reuters)

“Tiger and Turtle–Magic Mountain” by German art duo Heike Mutter and Ulrich Genth is a walkable sculpture shaped like a roller coaster. Visitors can stroll along the track (except for the loop sections). The 69 foot tall sculpture is located in Wanheim Duisburg, Germany.

Ariadne Ioannou attends the CARS 2 Germany Premiere at the Mathaeser Filmpalast on July 28, 2011 in Munich, Germany. (Photo by Hannes Magerstaedt/Getty Images)

Players of the USA celebrate in the dressing room following their team's victory in the 2019 FIFA Women's World Cup France Final match between The United States of America and The Netherlands at Stade de Lyon on July 07, 2019 in Lyon, France. (Photo by Maddie Meyer – FIFA/FIFA via Getty Images)

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)

A knight parades in the street during the traditional carnival parade in Cologne, western Germany, Monday, February 16, 2015. (Photo by Martin Meissner/AP Photo)

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)

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)