Labourers stack dried bricks inside a kiln, where they will be fired, at a brick factory on the outskirt of Sanaa, Yemen, June 1, 2016. Traditional mud brick tower houses have always been a source of pride to Yemenis, and over a year into a devastating civil war, they are also providing some much-needed jobs in the ancient capital Sanaa. (Photo by Mohamed al-Sayaghi/Reuters)

In this photo posted on Twitter, Sunday, May 3, 2015, and provided by NASA, Italian astronaut Samantha Cristoforetti sips espresso from a cup designed for use in zero-gravity, on the International Space Station. Cristoforetti, the first Italian woman in space, fired up the first espresso machine in space, which uses small capsules, or pods, of espresso coffee. (Photo by AP Photo/NASA)

Dilwyn Green, from North Wales, holds his 7 month old Gold Silkie Bantam which won a 1st prize in its breed at the Poultry Club's 2011 National Show on November 19, 2011 in Stoneleigh, England. (Photo by Oli Scarff/Getty Images)

Miniature pig “Nueffel” is walked in a park in Hanover, Germany, 14 April 2016. (Photo by Sebastian Gollnow/EPA)

Women wearing sunglasses pose for a group photo at a park in Beijing in 1980. (Photo by Reuters/China Daily)

An infrared portrait from NASA's Spitzer Space Telescope which shows generations of stars is seen in this undated NASA handout image released February 14, 2013. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. (Photo by NASA/Reuters/JPL-Caltech/Harvard-Smithsonian/Handout)

This photo released by the Cleveland Animal Protective League shows Lurleen, the nursing mother and Noland the puppy snuggling up Wednesday, June 19, 2013, in Cleveland. Lurleen already is caring for four newborn kittens and now is nursing the orphaned week-old pit bull puppy in Cleveland. (Photo by AP Photo/Cleveland Animal Protective League)

Three very colouful alpacas enjoy the hot weather at Toft Farm, Rugby, on July 19, 2013. (Photo by Caters News)