A model wears a floral head dress as she promotes a chain of garden centres at the Royal Horticultural Soceity's Chelsea Flower Show in London, Britain, May 18, 2015. (Photo by Toby Melville/Reuters)

Andrea Petkovic of Germany in action against Sara Errani of Italy during day one of the Mutua Madrid Open tennis tournament at the Caja Magica on May 3, 2014 in Madrid, Spain. (Photo by Julian Finney/Getty Images)

Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)

People walk by a car destroyed by a tree which fell during a storm and strong winds, in Limoges, on May 21, 2014. High winds upto 120 km/h and storms have caused at least one death and cut off some 42 000 homes from electricity today in the Midi-Pyrenees region of France. (Photo by Pascal Lachenaud/AFP Photo)

A sloth peeks out from behind a door on a floating house in the “Lago do Janauari” near Manaus, Brazil, Tuesday, May 20, 2014. Manaus is one of the host cities for the 2014 World Cup in Brazil. (Photo by Felipe Dana/AP Photo)

Ukrainians pour water on each other on a street in Lviv, Ukraine, 02 May 2016. The tradition of pouring water was an ancient spring ritual of cleansing on first Monday after Orthodox Easter. (Photo by Mykola Tys/EPA)

People walk past the Sleepwalker, a sculpture along the High Line in New York, US on May 10, 2016. The hyperrealistic work by Brooklyn artist Tony Matelli is part of the linear park’s Wanderlust exhibition. (Photo by Xinhua/Barcroft Images)

A picture made available on 13 May 2016 shows A Tiwa girl performing her traditional dance as they celebrated the Wanchuwa festival in Karbi Anglong District of Assam state, India, 11 May 2016. Wanchuwa is one of the most important festivals of the Tiwa tribal community living in the hills as it is related with agriculture which is the mainstay of their economy. Tiwas pray for a bountiful harvest during this festival and to protect their crops from pest and other natural calamities. Tiwa is a major tribe of Assam state who practice Jhum or shifting cultivation for their living in the hills. (Photo by EPA/Stringer)