Naga Sadhus or Hindu Holy men leave after taking a dip during the first "Shahi Snan" (grand bath) at “Kumbh Mela” or the Pitcher Festival, in Prayagraj, previously known as Allahabad, India, January 15, 2019. (Photo by Danish Siddiqui/Reuters)

A Sadhu or a Hindu holy man carrying his pet monkey walks after taking a dip at the confluence of the river Ganges and the Bay of Bengal on the occasion of “Makar Sankranti” festival at Sagar Island, south of Kolkata, India, January 14, 2017. (Photo by Rupak De Chowdhuri/Reuters)

A tourist take a photograph of a sulphur lake in the Danakil Depression on January 23, 2017 near Dallol, Ethiopia. The depression lies 100 metres below sea level and is one of the hottest and most inhospitable places on Earth. Despite the gruelling conditions, Ethiopians continue a centuries old industry of mining salt from the ground by hand in temperatures that average 34.5 degrees centigrade but have risen to over 50 degrees. (Photo by Carl Court/Getty Images)

A man takes a photograph of his friend as thick smoke rises from a fire, which broke out at oil wells set ablaze by Islamic State militants before they fled the oil-producing region of Qayyara, Iraq, January 28, 2017. (Photo by Muhammad Hamed/Reuters)

Janelle Monae (L) and Taraji P. Henson pose with the SAG Award for Outstanding Cast in a Motion Picture award for “Hidden Figures”, during the 23rd annual Screen Actors Guild Awards ceremony at the Shrine Exposition Center in Los Angeles, California, USA, 29 January 2017. (Photo by Paul Buck/EPA)

These images give a rare insight into the life of a 19th Century Indian Maharajah. Maharajah Ram Singh ruled in the famous pink city of Jaipur between 1835 and 1880, and was also a keen photographer. Here: Full portrait of a woman in the harem in the royal palace of Jaipur, India, 1857 – 1865. (Photo by Maharaja Ram Singh III/Alinari via Getty Images)

A woman reacts after performing Otonamaki, which translates as “adult wrapping”, a new form of therapy where people are wrapped in large swaddling cloth to alleviate posture problems and stiffness, at a session in Asaka, Saitama prefecture, Japan, February 4, 2017. (Photo by Toru Hanai/Reuters)

A woman wears a face mask in the part of the city near neighbourhoods known for burning coal for heating in Ulaanbaatar, Mongolia January 26, 2017. Not many people in Ulaanbaatar wear masks to protect themselves against pollution. (Photo by B. Rentsendorj/Reuters)