Stones collected and categorised by shape (fish) are seen at the home workshop of Luigi Lineri in Zevio, near Verona, Italy, June 10, 2016. Luigi Lineri's home workshop is covered in stones – tens of thousands of them. They resemble animal heads, human faces and other forms, and the artist and poet believes may have been shaped by prehistoric humans. (Photo by Alessandro Bianchi/Reuters)

An elephant is used to demolish a house during an eviction drive inside Amchang Wildlife Sanctuary on the outskirts of Gauhati, Assam, India, Monday, November 27, 2017. Indian police on Monday took the unusual step of using elephants in an attempt to evict hundreds of people living illegally in the protected forest area in the country's remote northeast. Police used bulldozers and the elephants in a show of force, and the forest dwellers responded by hurling rocks. (Photo by Anupam Nath/AP Photo)

A saltwater crocodile with a tyre around its neck is seen in Palu river in Palu on January 16, 2018. Indonesian conservation officials are racing against time to locate and rescue a saltwater crocodile that has had a tire wrapped around its for more than a year on the island of Sulawesi. (Photo by AFP Photo/ARFA)

Aerial view of CRH bullet trains setting out ahead of Spring Festival travel rush on January 31, 2018 in Hefei, Anhui Province of China. About 2.98 billion trips will be made during the 40-day Spring Festival travel rush. China will take multiple measures to ensure a smooth Spring Festival travel rush. (Photo by VCG/VCG via Getty Images)

Martin Lacey Jr. with a lion during the premiere of the Circus Krone program “Circus der Preistraeger” at Circus Krone on February 2, 2016 in Munich, Germany. (Photo by Hannes Magerstaedt/Getty Images)

Disguised revellers parade on the occasion of the Cortege during the Carnival in Basel, Switzerland, February 17, 2016. (Photo by Georgios Kefalas/EPA)

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/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)