A woman takes part in a global March for marijuana in Medellin, Colombia, May 7, 2016. The Global Marijuana March (GMM) is an annual rally held at different locations across the planet. It refers to cannabis-related events that occur on the first Saturday in May, or thereabouts, and may include marches, meetings, rallies, raves, concerts, festivals and information tables. (Photo by Fredy Builes/Reuters)

Swiss police officers stand beside of mock gates of the NEAT Gotthard Base Tunnel inside the event hall for the upcoming opening ceremony near the town of Erstfeld, Switzerland May 31, 2016. The celebrations of the opening of the Gotthard Base Tunnel will start on June 1, 2016. With a length of 57 km (35 miles) crossing the Alps, the Gotthard Base tunnel is the world's longest train tunnel. (Photo by Arnd Wiegmann/Reuters)

A participant sets off on a penny-farthing bicycle at the start of the The Tweed Run in central London, Britain, May 14, 2016. The Tweed Run, a very British public bicycle ride through London's streets, with a prerequisite that participants are dressed in their best tweed cycling attire. (Photo by Hannah McKay/Reuters)

Dancers take part in the Karneval der Kulturen (Carnival of Cultures) street parade of ethnic minorities in Berlin, Germany, May 15, 2016. (Photo by Hannibal Hanschke/Reuters)

A girl sits on her boat at a Bak Angrout dried up pond at the drought-hit Kandal province in Cambodia May 13, 2016. (Photo by Samrang Pring/Reuters)

Mohamed Gamal Abdel Nasser, a workshop owner, tests primus stoves known as “Bagour” in Arabic, in Cairo, Egypt, May 11, 2016. (Photo by Mohamed Abd El Ghany/Reuters)

A model walks the runway during the Di$count Universe show at Mercedes-Benz Fashion Week Resort 17 Collections at Carriageworks on May 18, 2016 in Sydney, Australia. (Photo by Stefan Gosatti/Getty Images)

Morenada dancers perform during the “Senor del Gran Poder” (Lord of Great Power) parade in La Paz, May 21, 2016. (Photo by David Mercado/Reuters)