In this April 23, 2015 photo, friends Jia Haixia, left, and Jia Wenqi work to plant a tree in a field in Yeli village near Shijiazhuang city in northern China's Hebei province. For the past 13 years, Jia Wenqi, who has no arms, and Jia Haixia, who is blind, have worked together to plant and water more than 12,000 trees near their village. (Photo by Helene Franchineau/AP Photo)

These images capture the intricate details of minuscule snowflakes, moments before they melt. The shots were taken by Don Komarechka, 31, who has had a lifelong fascination with all things macro – especially snowflakes. The professional photographer says people often don’t believe that his pictures are real because they’re so perfect. (Photo by Don Komarechka/Caters News Agency)

Lucie Clayton instructs pupils in the art of correct posture by balancing a glass and book on their heads at her finishing school in Old Cavendish Street, London. (Photo by William Vanderson/Fox Photos/Getty Images). 25th November 1936

Afghan children wait as their mothers receive treatment at a USAID-funded health center on September 7, 2011 in Farza, Afghanistan. Almost 10 years after the 9/11 attacks and the U.S. invasion of Afghanistan, the U.S. government funds some of 500 Afghan health facilities nationwide, most run by non-governmental organizations contracted by the Afghan Ministry of Public Health. (Photo by John Moore/Getty Images)

Revellers ride during the 54th annual brass band festival in the Serbian village of Guca August 7, 2014. Every year Guca is swamped by thousands of people taking part in the celebration of brass band music. (Photo by Marko Djurica/Reuters)

Indian students play with coloured powders as they celebrate “holi” or the “festival of colours” during a special function in Kolkata on March 12, 2017. Holi, the popular Hindu spring festival of colours, is observed in India at the end of the winter season on the last full moon of the lunar month, and will be celebrated on March 13 this year. (Photo by Dibyangshu Sarkar/AFP Photo)

Auxiliary Territorial Service (ATS) plotters at work at Coastal Artillery Headquarters in Dover, December 1942. The Auxiliary Territorial Service was the women's branch of the British Army during the Second World War. It was formed on 9 September 1938, initially as a women's voluntary service, and existed until 1 February 1949, when it was merged into the Women's Royal Army Corps. The ATS had its roots in the Women's Auxiliary Army Corps (WAAC), which was formed in 1917 as a voluntary service. During the First World War its members served in a number of jobs including clerks, cooks, telephonists and waitresses. The WAAC was disbanded after four years in 1921. (Photo by Ted Dearberg/IWM/PA Wire)

A boy looks for scrap metal using an improvised magnetic tool near a construction site in New Delhi, India, March 21, 2016. (Photo by Cathal McNaughton/Reuters)