A view of the construction site of the Chateau de Guedelon near Treigny in the Burgundy region of France, September 13, 2016. Blacksmiths, stonemasons and quarry men are hard at work in a Burgundy forest building a 13th-century-style castle using the most basic tools and materials, replicating the methods used hundreds of years ago to better understand them. (Photo by Jacky Naegelen/Reuters)

Google has built its first self-driving car prototypes and hopes to test hundreds more models this summer. If all goes well, the company is planning a pilot program in California over the next few years.

In this July 17, 2015 photo, Michael Chilton squeezes into a corner of his car to make a quick repair to some body panels after he ran into a wall during dirt track racing in the late model division at the Ponderosa Speedway in Junction City, Ky. He banged up the car in the qualifying round and had a few minutes to fix it before the final race. (Photo by David Stephenson/AP Photo)

The Air2 (Air Squared) floating Bluetooth speaker from Axxess CE is displayed at CES Unveiled, the opening event for the media preview days at the 2015 Consumer Electronics Show, January 4, 2015 in Las Vegas, Nevada. The speaker which levitates over its own base is one of the winners for the CES Innovation Awards and is patent pending. (Photo by Robyn Beck/AFP Photo)

Tiny pieces of space rocks, called meteorites, are seen burning in the atmosphere over the night sky near Salgótarján, some 109km northeast of Budapest, Hungary, 21 April 2018 (issued 22 April 2018). (Photo by Peter Komka/EPA/EFE)

A detailed view of the BMW 1600 during the The 40th Antwerp Classic Salon run by SIHA Salons Automobiles and held at Antwerp EXPO Halls on March 3, 2017 in Antwerpen, Belgium. (Photo by Dean Mouhtaropoulos/Getty Images)

A visitor looks down from a terrace at a Volkswagen Beetle owners' meeting in Sao Bernardo do Campo January 25, 2015. Around 1000 Volkswagen Beetle cars took part in this event as part of celebrations marking Brazil's annual National Volkswagen Beetle day, which falls on January 20. (Photo by Paulo Whitaker/Reuters)