Smithsonian National Zoo biologist Leigh Pitsko releases a male lion cub for its swim test in the zoo habitat moat, in Washington May 6, 2014. Four, unnamed ten-week old lion cubs were tested today for their ability to swim and remove themselves from their zoo habitat moat. (Photo by Gary Cameron/Reuters)

This is the moment a dog who had his legs cut off as a punishment, is able to walk again thanks to prosthetic limbs, and being rescued by John and Gill Dalley, a couple who moved to Phuket, Thailand, from Leeds to set up the Soi Dog Foundation, August 1, 2016. (Photo by Caters News Agency)

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.

The front wheels of a tractor, pulling a trailer overloaded with sugarcane, are seen lifted off the ground as it passes through the streets of Karor Lan Esan, Pakistan December 6, 2015. (Photo by Caren Firouz/Reuters)

A mother prays for success for her child in the college entrance examinations at a Buddhist temple in Seoul, South Korea, November 12, 2015. About 630,000 students on Thursday sat for the annual exams that could lead them to one of the country's top universities. In South Korea, there is no higher achievement than to be accepted by a prestigious university. As a result, many students prepare for these entrance exams from an early age, often studying up to 16 hours a day for years to take this test. (Photo by Kim Hong-Ji/Reuters)

Competitors Hope Garcia (L) and Francesca Esker during the newly reintroduced Muscle Beach Vintage Swimsuit competition at Venice Beach, California on May 30, 2016. Venice is one of two historic bodybuilding locations and took over as the most famous spot when the nearby Santa Monica Muscle beach was shutdown due to overcrowding. California Governor and actor Arnold Schwarzenegger used to be a regular amongst the many famous bodybuilders and actors who have trained there and still makes an occasional appearance. (Photo by Mark Ralston/AFP Photo)

The hard-worked hands of Jacaba Coaquira, 80, holding the green beans she grew on her land. This year the production of her land was affected by lack of rain and early cold weather that froze the crops before they finished growing. Santiago de Okola, Bolivia. (Photo by Renée C. Byer/Living on a Dollar a Day)

A Balinese Hindu blows fire, during a parade carrying Ogoh-ogoh effigies symbolising evil spirits, during a ritual before Nyepi, the day of silence, in Palembang, South Sumatra province, Indonesia March 8, 2016. Nyepi is a day of silence for self-reflection celebrating the Balinese Hindu new year, where people may not use lights, light fires, work, travel nor enjoy entertainment. (Photo by Darren Whiteside/Reuters)