Robot couple Xiaolan (L) and Xiaotao carry trays of food at a restaurant in Jinhua, Zhejiang province, China, May 18, 2015. The restaurant, which opened on Monday, has two robots delivering food for customers. The robots were designed as a couple, Xiaolan and Xiaotao, according to local media. (Photo by Reuters/Stringer)

A couple embrace during the start of the San Fermin festival in Pamplona, Spain July 6, 2016. Revelers from around the world kick off the festival with a messy party in the Pamplona town square, one day before the first of eight days of the running of the bulls. (Photo by Vincent West/Reuters)

Lilly Caron, 8, of Bridgeton, Maine, Jason Homchick, of San Diego, and Lilly's father Jason Caron, (obscured), ride the Sky Swing at Seacoast Adventure, Thursday, July 14, 2016, in Wyndham, Maine. The 100-foot-tall swing gives riders the combined thrills of sky diving and hang gliding. (Photo by Robert F. Bukaty/AP Photo)

Undated handout photo issued by Guinness World Records of Fabio Reggiani from Italy who has made it into the Guinness Book of World Records for constructing the worlds largest rideable motorcycle measuring 5.10 meters (16ft 8.78 in) from the ground to the top of the handlebars. Six times larger than a normal motorcycle, it's 10.03 m long, 2.5 m wide, and weighs approximately 5,000 kg (5 tonnes). (Photo by Guinness World Records/PA Wire)

A demonstrator jumps from a vehicle of the Organisation for Security and Co-operation in Europe (OSCE) during a protest to demand what protesters say is true information from the OSCE about the shelling in Donetsk, Ukraine (since April 2014, the city is the administrative centre of the Donetsk People's Republic), July 23, 2015. The graffiti reads, “Stop moronic war!”. (Photo by Alexander Ermochenko/Reuters)

A woman rides a donkey during a donkey race in Roum village, Jizeen countryside, southern Lebanon, August 9, 2015. (Photo by Ali Hashisho/Reuters)

Rita Ora attends the World Premiere of JEREMY SCOTT: THE PEOPLE'S DESIGNER, presented by The Vladar Company and Quintessentially at the TCL Chinese Theatre on Tuesday, September 8, 2015, in Hollywood, Calif. (Photo by Matt Sayles/Invision for The Vladar Company/AP Images)

A woman aims a World War II machine gun at a military show during celebration of the Defenders of the Fatherland Day in St.Petersburg, Russia, Tuesday, February 23, 2016. The day, celebrated in Russia on February 23, honors the nation's military and is a nationwide holiday. (Photo by Dmitri Lovetsky/AP Photo)