Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)

Colorado Gov. John Hickenlooper shows off his socks--one with Democratic presidential candidate Bernie Sanders and the other with Republican candidate Donald Trump – before entering his former brewpub for a book signing event to mark the release of his autobiography Thursday, May 26, 2016, in Denver. Hickenlooper, who is term-limited, is doing book talk rounds this week, reviving speculation that he is positioning himself to join Hillary Clinton's presidential campaign ticket. (Photo by David Zalubowski/AP Photo)

Participants compete in the Mud Day Race extreme run competition at El Goloso military base, outside Madrid, Spain, June 11, 2016. Thousands of athletes got covered in mud as they celebrated International Mud Day running a 13-kilometer obstacle course on a sunny Saturday with heatwave-like temperatures up to a 29 degrees Celcius (around 84 degrees Fahrenheit). (Photo by Juan Medina/Reuters)

“Custer” the smallest car in the US. (Photo by Topical Press Agency/Getty Images). 1920

A student of the department for aritificial intelligence at the Freie Universitaet Berlin steers a converted Dodge minivan remotely with an iPhone during a demonstration at Tempelhof Airport on November 2, 2009 in Berlin, Germany. The car, whose design was led by professor Raul Rojas, is outfitted with a variety of laser sensors, GPS antennae and computers. (Photo by Sean Gallup/Getty Images)

A woman looks at La Paz city from the Jacha Qhatu cable car station in El Alto, July 23, 2015. Bolivia already has the largest urban cable car system in the world. Now the booming country is tripling the size of the network and will soon have nine lines whizzing above the administrative capital of La Paz. (Photo by David Mercado/Reuters)

Michael Fröhlich's Jowett Javelin rotting car in his forest sculpture park in Neandertal Germany, September 11, 2016. An eccentric artist has collected fifty vintage cars and left them to rot in a forest – and now they're worth over $1 million. Former racing driver Michael Fröhlich, from Dusseldorf, Germany, has purposely crashed the cars into trees, buried them in mud and parked them on cliff faces in his estate's garden in the middle of the German Neanderthal. His collections includes a Jaguar XK120 worth $170,000, a Porsche 356 racer and a Buick worth $17,000. (Photo by Christoph Hagen/Barcroft Images)

Participants fancy dressed go downhil in the XXVII Car Festival in a homemade cart in the Santa Elena Municipality, near Medellin, Antioquia department, Colombia, on December 18, 2016. (Photo by Raul Arboleda/AFP Photo)