Microsoft co-founder Paul Allen has spent the last six years working on a giant aircraft capable of launching rockets to space. Today, his company Stratolaunch Systems literally rolled that plane out of its hangar in the Mojave Desert for the first time ever.

Two children jumping through a water hydrant's shower on a New York street. They have come from a neighbouring co-educational playgroup organised by the city's Police Department. (Photo by Orlando/Getty Images). 1950

iPhone 4 hard case cover with portrait of Steve Jobs are on sale on October 9, 2011 in Shenzhen, Guangdong Province of China. Apple co-founder Jobs died on October 5, 2011 at the age of 56. (Photo by ChinaFotoPress/Getty Images)

Trainers from Tianjiao Special Guard/Security Consultant Ltd. Co. engage trainees dressed in swimming suits as they crawl on the beach during a training session in Sanya, Hainan province January 8, 2012. (Photo by CHINA DAILY/Reuters)

Japan's electronics equipment maker MuRata Manufacturing Co., Ltd's showcased their bicycle-riding robot “MuRata Boy” during the CEATEC Japan 2006 exhibition on October 3, 2006 in Chiba, Japan. The “MuRata Boy” robot can ride up a 25-degree slope, stop without losing its balance and make an S-curve without falling. (Photo by Koichi Kamoshida/Getty Images)

Nottingham-based Vic Fearn & Co. has created unusual coffins in the shape of beer and whiskey bottles, the Angel of the North, guitars and in a geometric style. The handmade caskets cost as much as £5,000 ($6,200). Here: A coffin in the shape of a fish which has been handmade. (Photo by Caters News Agency)

A student aims a stick of wood at Bolivarian National Police officers during clashes outside the Central University in Caracas, Venezuela, Thursday, June 9, 2016. Students had planned to march from Venezuela's top university to elections headquarters, but hundreds of police in riot gear blocked the way. Students covered their faces with Venezuelan flags and threw bottles, stones and sticks while police lobbed tear gas. (Photo by Fernando Llano/AP Photo)

A child coughs as migrants and refugees run away after Macedonian police fired tear gas at hundreds of Iraqi and Syrian migrants who tried to break through the Greek border fence in Idomeni, on February 29, 2016. Greek police said more than 6,000 people were massed at the border, in a buildup triggered by Austria and Balkan states capping the numbers of migrants entering their territory. (Photo by Louisa Gouliamaki/AFP Photo)