A model prepares backstage ahead of the Amber & Thomas show during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 3, 2011 in Sydney, Australia. (Photo by Ryan Pierse/Getty Images)

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Lake Natron is a salt lake located in northern Tanzania, close to the Kenyan border, in the eastern branch of the East African Rift. The lake is fed by the Southern Ewaso Ng'iro River and also by mineral-rich hot springs. It is quite shallow, less than three meters (10 feet) deep, and varies in width depending on its water level, which changes due to high levels of evaporation, leaving concentrations of salt and other minerals, notably sodium carbonate (natron).

A team from Woody's Ice Cream shop wrangle a large inflatable dinosaur down the street during the Independence Day Parade in Fairfax, Virginia July 4, 2015. Americans marched in star-spangled parades, ran relay races, gathered for fireworks shows and crowned a new world hot dog eating champion as they celebrated Independence Day in traditional style on Saturday. (Photo by Jonathan Ernst/Reuters)

Vogue Italia is hosting a series of shows in Milan exploring how the magazine seeks to engage with hot social and political issues and provoke debate through images by top photographers. The Photo Vogue festival in Milan is hosting three exhibitions. The first, Fashion and Politics in Vogue Italia, looks at the magazine’s ambition to be a catalyst for change – in subtle and playful ways. Here: David LaChapelle – October 2004. (Photo by David LaChapelle/The Guardian)

A life size animatronic Tyrannosaurus Rex dinosaur arrives at Bristol Zoo Gardens on May 14, 2012 in Bristol, England. Twelve animatronic dinosaurs arrived at Bristol Zoo Gardens this morning after being transported in crates from Texas, USA. They will form part of the zoo's summer exhibition “DinoZoo” which opens later this month. (Photo by Matt Cardy)

LONDON - JUNE 04: A piece entitled “Entrance into wood” by Elke Krystufek goes on show at The Royal Academy Summer Exhibition on June 4, 2008 in London. In it's 240th year, the exhibition displays a wide range of recent work by both established and emerging artists. 10,000 artists submitted work for selection this year. (Photo by Peter Macdiarmid/Getty Images)

Models pose backstage ahead of the Gary Bigeni show during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 4, 2011 in Sydney, Australia. (Photo by Matt King/Getty Images)

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.