Chinese People's Liberation Army (PLA) navy personnel stand guard on their Jiangkai II class vessel, CNS Yulin, during a display of warships ahead of the IMDEX Asia maritime defence exhibition at Changi Naval Base in Singapore May 18, 2015. The 10th international maritime defence show which sees participation from 180 exhibitors and delegations from over 40 countries takes place from May 19 to 21. (Photo by Edgar Su/Reuters)

A U.S. Navy personnel stands next to a Vertical Takeoff and Landing (VTOL) unmanned aerial vehicle MQ-8B Fire Scout displayed onboard USS Fort Worth, ahead of the IMDEX Asia maritime defence exhibition in Singapore May 18, 2015. (Photo by Edgar Su/Reuters)

A waitress places dishes on a tray carried by a robot couple at a restaurant in Jinhua, Zhejiang province, China, May 18, 2015. The restaurant, which opened on Monday, has two robots delivering food for customers. The robots were designed as a couple, Xiaolan and Xiaotao, according to local media. (Photo by Reuters/Stringer)

Robot Xiaotao delivers food at a restaurant in Jinhua, Zhejiang province, China, May 18, 2015. (Photo by Reuters/Stringer)

Robot couple Xiaolan (L) and Xiaotao carry trays of food at a restaurant in Jinhua, Zhejiang province, China, May 18, 2015. (Photo by Reuters/Stringer)

A woman cleans a World War Two monument to Red Army soldiers and to workers of the rear in the centre of Irkutskoye village, north of the Siberian city of Krasnoyarsk, Russia, May 18, 2015. Residents of the remote, sparsely inhabited village look after the monument, though the date and details of its creation are not known. (Photo by Ilya Naymushin/Reuters)

A visitor (C) rests at the Acropolis museum in Athens May 18, 2015. Museums across Greece offered free admission to visitors on Monday to celebrate International Museum Day. (Photo by Alkis Konstantinidis/Reuters)

A man looks at the 140 B.C. bronze statue of a young jockey riding a horse during the International Day Museum with free entrance for the visitors, at the Archeological museum in Athens on Monday, May 18, 2015. Greece's cash-strapped government signaled Monday it needs a deal with bailout lenders by the end of the month to keep up loan repayments though the summer, as renewed concern rattled markets and saw borrowing rates shoot up. (Photo by Thanassis Stavrakis/AP Photo)

Tanzanians sail on a commercial boat with their belongings on the shores of Lake Tanganyika near Kigoma in western Tanzania, May 18, 2015. (Photo by Thomas Mukoya/Reuters)

Haitian children show their skills during a march in celebrations for National Haitian Flag Day in the streets of Port-au-Prince, May 18, 2015. Haitians are celebrating the 212th anniversary of their national flag. (Photo by Andres Martinez Casares/Reuters)

A woman carries bananas at a plantation in Caxito, Angola, May 14, 2015. After decades of civil war destroyed Angola's fertile farmland and a booming oil industry pushed out all other commerce, banana plantations are thriving again in the tropical plains of Caxito, to such an extent that Angola, which imports 90 percent of its food at a cost of $5 billion a year, has finally been able to stop importing bananas. It's a rare case of agricultural progress in a country where only 30 percent of land is cultivated. (Photo by Herculano Coroado/Reuters)

Rows of raw ivory tusks that were seized by Singapore authorities are displayed in this handout photo provided on May 19, 2015 by Agri-Food and Veterinary Authority of Singapore (AVA). The AVA and Singapore Customs and Immigration and Checkpoints Authority (ICA) on Tuesday said a shipment of about 3.7 tonnes of illegal ivory was seized. The shipment, which was declared as tea leaves, was seized from two 20-foot containers from Kenya in transit through Singapore for Vietnam. The estimated haul of S$8 million ($6 million) consisting of 1783 pieces of whole and cut raw ivory tusks, four rhinoceros horns and 22 pieces of canine teeth believed to be from African big cats, are now with the AVA for further investigations. This is the second largest seizure of illegal ivory since 2002, reported local media. (Photo by Reuters/Agri-Food and Veterinary Authority of Singapore)

AVAAZ environmental activists wear masks depicting leaders of the countries members of the G7, (L-R) Japanese Prime Minister Shinzo Abe, British Prime Minister David Cameron, French President Francois Hollande, German Chancellor Angela Merkel, U.S. President Barack Obama, Italian Prime Minister Matteo Renzi and Canadian Prime Minister Stephen Harpe during a rally in front of the Brandenburg Gate near the venue where the Petersberg Climate Dialogue takes place in Berlin, Germany, May 19, 2015. (Photo by Fabrizio Bensch/Reuters)

Sonja Heiniger, 76 years old, looks under the hood of her Lamborghini in Jona, Switzerland, March 20, 2015. Supercar makers are like teenage boys at a high school dance, according to business consultant Belinda Parmar. They don't have a clue how to speak to women. They may need to learn, and quickly. With the number of financially independent women on the rise across much of the world, high-performance carmakers risk losing a potentially big market to more adaptable rivals. (Photo by Alessandro Garofalo/Reuters)

Cathay Pacific flight attendants participate in a protest at the departure hall of the Hong Kong Airport, China May 19,2015. Cathay Pacific Airways Flight Attendants Union started a sit in protest at the airport on Tuesday, after failed talks with management over pay and working conditions, local media reported. (Photo by Tyrone Siu/Reuters)

A Cathay Pacific flight attendant carries a sign while participating in a protest at the departure hall of the Hong Kong Airport, China May 19,2015. (Photo by Tyrone Siu/Reuters)

Visitors walk past aircrafts at the static display area during the European Business Aviation Convention & Exhibition (EBACE) at Cointrin airport in Geneva, Switzerland, May 19, 2015. (Photo by Denis Balibouse/Reuters)

Visitors stand next to a WACO aircraft during the 15th Annual European Business Aviation Convention and Exhibition, EBACE, at the Geneva Palexpo Conference Center located adjacent to the Geneva Airport in Geneva, Switzerland, Tuesday, May 19, 2015. (Photo by Salvatore Di Nolfi/Keystone via AP Photo)

A girl, wearing a red neckerchief, a symbol of the Young Pioneer Organisation, salutes during a ceremony for the inauguration of 45 newly adopted members on the day of its anniversary at school-lyceum number 12 in the Siberian city of Krasnoyarsk, Russia, May 19, 2015. On this day in 1922, early pro-communist movements which appeared in Russia after the 1917 Bolshevik revolution were reformed into the Young Pioneer Organisation of the Soviet Union. While the organisation lost its dominance among students in post-Soviet Russia, some families and educational institutions, including school-lyceum number 12 which is the only one of this kind in Krasnoyarsk, still carry on this tradition. (Photo by Ilya Naymushin/Reuters)

Children, wearing red neckerchiefs, a symbol of the Young Pioneer Organisation, play the drums during a ceremony for the inauguration of 45 newly adopted members on the day of its anniversary at school-lyceum number 12 in the Siberian city of Krasnoyarsk, Russia, May 19, 2015. (Photo by Ilya Naymushin/Reuters)

Children, holding red neckerchiefs, a symbol of the Young Pioneer Organisation, line up during a ceremony for the inauguration of 45 newly adopted members on the day of its anniversary at school-lyceum number 12 in the Siberian city of Krasnoyarsk, Russia, May 19, 2015. (Photo by Ilya Naymushin/Reuters)

Children, wearing red neckerchiefs, a symbol of the Young Pioneer Organisation, salute during a ceremony for the inauguration of 45 newly adopted members on the day of its anniversary at school-lyceum number 12 in the Siberian city of Krasnoyarsk, Russia, May 19, 2015. (Photo by Ilya Naymushin/Reuters)

A burnt multi-storey residential building is seen in Baku, Azerbaijan, May 19, 2015. At least 16 people were killed and dozens wounded on Tuesday in a fire that ripped through a multi-storey residential building in Azerbaijan's capital, Baku, local news agency APA reported. (Photo by Ehtiram Jabi/Reuters)

A police officer and a fire fighter help child victim of an apartment building fire in Baku, Azerbaijan, Tuesday, May 19, 2015. Azerbaijani officials say 16 people have died and more than 50 have been injured in a fire at an apartment building in Baku, the capital. The massive fire quickly engulfed 16-story apartment building Tuesday and took hours to contain. Azerbaijan's chief prosecutor, Zakir Garalov, said the bad quality of plastic paneling covering the building contributed to the fire and a criminal probe has been launched to determine the culprits. (Photo by Orxan Azim/AP Photo)

A rescuer descends from a helicopter over the roof of a burnt multi-storey residential building in Baku, Azerbaijan, May 19, 2015. (Photo by Ehtiram Jabi/Reuters)

The Villarrica Volcano is seen partially covered by clouds at Pucon, Chile, May 18, 2015. Picture taken May 18, 2015. (Photo by Cristobal Saavedra/Reuters)

The Villarrica Volcano is seen partially covered by clouds at Pucon, Chile, May 18, 2015. Picture taken May 18, 2015. (Photo by Cristobal Saavedra/Reuters)

The Villarrica Volcano is seen partially covered by clouds at Pucon, Chile, May 19, 2015. (Photo by Cristobal Saavedra/Reuters)

The Villarrica Volcano is seen partially covered by clouds at Pucon, Chile, May 19, 2015. (Photo by Cristobal Saavedra/Reuters)

A poster supporting the Yes vote is displayed in the Dame street area of Dublin in Ireland May 19, 2015. Irish voters are set to back the introduction of gay marriage by a margin of as much as two-to-one and become the first country to approve the policy in a national plebiscite, a series of polls have indicated. (Photo by Cathal McNaughton/Reuters)

Pilgrims from the Ronda brotherhood make their way to the shrine of El Rocio in Coria del Rio, southern Spain May 19, 2015. Every spring hundreds of thousands of devotees converge at a shrine to pay homage to the Virgin del Rocio during an annual pilgrimage which combines religious fervour and festive colour. (Photo by Marcelo del Pozo/Reuters)

Pilgrims from the Fuengirola brotherhood embrace on their way to the shrine of El Rocio in Coria del Rio, southern Spain May 19, 2015. (Photo by Marcelo del Pozo/Reuters)

A pilgrim from the Fuengirola brotherhood sits on her way to the shrine of El Rocio in Coria del Rio, southern Spain May 19, 2015. (Photo by Marcelo del Pozo/Reuters)

A woman sorts through a pile of cashew nuts as children look on next to a farm owned by former Guinea Bissau army chief General Antonio Indjai outside Mansoa, Guinea-Bissau, May 8, 2015. Relaxing in flip-flops in a shady corner of his farm near a pile of freshly-raked cashew nuts, the former head of Guinea Bissau's army General Antonio Indjai says he has turned in his weapons and his days as a coup leader are over. For many, Indjai is a symbol of all that went wrong in the former Portuguese colony that is one of Africa's most fragile states. Since 1980, Guinea Bissau has suffered nine coups or attempted coups, including one led by Indjai in 2012 that led to two years of public looting and a surge in drug trafficking. (Photo by Emma Farge/Reuters)

Former army chief General Antonio Indjai shows a machete used on his farm as male relatives look on outside Mansoa, Guinea-Bissau, May 8, 2015. (Photo by Emma Farge/Reuters)

Money changers wait for customers at a local bureau where $100 U.S. dollars exchange for 750,000 Somaliland shillings in Hargeysa, Somalia May 19, 2015. (Photo by Feisal Omar/Reuters)

A man carries bundles of local currency near a money exchange bureau where $100 U.S. dollars change for 750,000 Somaliland shillings in Hargeysa May 19, 2015. (Photo by Feisal Omar/Reuters)

A woman waits to change money at a local bureau where $100 U.S. dollar exchange for 750,000 Somaliland shillings in Hargeysa May 19, 2015. (Photo by Feisal Omar/Reuters)

Two U.S. Marine F-35B Lightning II Joint Strike Fighters complete vertical landings aboard the USS Wasp (LHD-1) during operational testing May 18, 2015. Picture taken May 18, 2015. (Photo by Lance Cpl. Remington Hall/Reuters/U.S. Marine Corps)

Last year's winner Conchita Wurst of Austria performs during the first semifinal of the upcoming 60th annual Eurovision Song Contest In Vienna, May 19, 2015. (Photo by Leonhard Foeger/Reuters)

Singer Eduard Romanyuta representing Moldova performs the song “I Want Your Love” during the first semifinal of the upcoming 60th annual Eurovision Song Contest In Vienna, May 19, 2015. (Photo by Leonhard Foeger/Reuters)

The band The Makemakes representing Austria perform the song “I am Yours” during the first dress rehearsal for the final of the upcoming 60th annual Eurovision Song Contest In Vienna, May 22, 2015. (Photo by Leonhard Foeger/Reuters)

A fisherman uses a shovel to pick up fish from his boat at the Artisanal Fishing Port in Jaramijo, Ecuador May 19, 2015. (Photo by Guillermo Granja/Reuters)

A fisherman groups and prepares shark fins at the beach of Manta, Ecuador May 19, 2015. (Photo by Guillermo Granja/Reuters)

Fisherman cut shark meat on a truck at the beach of Manta, Ecuador May 19, 2015. (Photo by Guillermo Granja/Reuters)

A fisherman poses while holding fish at the Artisanal Fishing Port in Jaramijo May 19, 2015. (Photo by Guillermo Granja/Reuters)

Members of Saudi special forces take part in a graduation ceremnoy held in Riyadh May 19, 2015. (Photo by Faisal Al Nasser/Reuters)

Members of Saudi special forces march during a graduation ceremony held in Riyadh May 19, 2015. (Photo by Faisal Al Nasser/Reuters)

Members of Saudi special forces take part in a graduation ceremnoy held in Riyadh May 19, 2015. (Photo by Faisal Al Nasser/Reuters)

Displaced Sunni people, who fled the violence in the city of Ramadi, arrive at the outskirts of Baghdad, May 19, 2015. Iraqi security forces on Tuesday deployed tanks and artillery around Ramadi to confront Islamic State fighters who have captured the city in a major defeat for the Baghdad government and its Western backers. (Photo by Reuters/Stringer)

Displaced Sunni people, who fled the violence in the city of Ramadi, arrive at the outskirts of Baghdad, May 19, 2015. (Photo by Reuters/Stringer)

An Iraqi Sunni displaced woman, who fled the violence in the city of Ramadi, carries her kid at the outskirts of Baghdad, May 19, 2015. (Photo by Reuters/Stringer)

An Iraqi Sunni displaced woman, who fled the violence in the city of Ramadi carries her child on the outskirts of Baghdad, Iraq May 19, 2015. (Photo by Reuters/Stringer)

Actor Dwayne “The Rock” Johnson poses with his hands in cement during his hand and footprints ceremony in the forecourt of the TCL Chinese Theatre in celebration of his new movie “San Andreas”, in Hollywood, California May 19, 2015. (Photo by Danny Moloshok/Reuters)