A boy somersaults at a traffic junction in Lima April 27, 2015. Children often perform on streets in Peru to make a living from tips given by drivers. (Photo by Mariana Bazo/Reuters)

A boy somersaults at a traffic junction in Lima April 27, 2015. (Photo by Mariana Bazo/Reuters)

A boy somersaults at a traffic junction in Lima April 27, 2015. (Photo by Mariana Bazo/Reuters)

A boy receives a tip after doing somersaults at a traffic junction in Lima April 27, 2015. (Photo by Mariana Bazo/Reuters)

Fans wait for the arrival of Paul McCartney before his gig at the Nippon Budokan Hall in Tokyo April 28, 2015. The gig marks McCartney's first return to the venue since he played there with the Beatles in 1966. (Photo by Thomas Peter/Reuters)

Filipino tribesmen participate in a wooden scooter race spanning 4.3 km (2.7 miles) in Banaue, Ifugao, north of Manila April 28, 2015. The race is part of the annual Imbayah festival. The festival showcases the rich culture and the ingenuity of the villagers whose ancestors carved the famous Ifugao rice terraces more than 2,000 years ago. (Photo by Harley Palangchao/Reuters)

A French journalist tries to disappear into the Cu Chi tunnel network through a hole camouflaged on the jungle floor during a guided tour some 70 km (44 miles) from Ho Chi Minh City (formerly Saigon City), Vietnam, April 28, 2015. The 200 km (124 miles) underground tunnel network includes sections for living, dining, meeting and fighting and was used during the resistance against the U.S. during the Vietnam War. Vietnam marks the 40th anniversary of the capture of Saigon by North Vietnamese forces on April 30, the event that ended a war that lasted over 30 years, killing up to four million Vietnamese, the Vietnamese government said, and more than 58,000 U.S troops, the U.S. Defense Ministry has said. Vietnam refers to the event as the date of its reunification. (Photo by Reuters/Kham)

Visitors have their photos taken near a tank used by the U.S. Army during the Vietnam War at the War Remnants Museum in Ho Chi Minh City, Vietnam, Wednesday, April 29, 2015. The city, formerly known as Saigon, is set to celebrate the 40th anniversary of the end of the Vietnam War on April 30. (Photo by Dita Alangkara/AP Photo)

World War Two veterans touch an exhibit showing Soviet leader Joseph Stalin at the Central Museum of the Great Patriotic War at the Poklonnaya Gora War Memorial Park in Moscow, Russia, April 28, 2015. Russia will celebrate the 70th anniversary of the victory over Nazi Germany in World War Two in May. (Photo by Sergei Karpukhin/Reuters)

Britain's opposition Labour Party leader Ed Miliband is seen through the viewfinder of a television camera as he speaks to supporters at Memorial Hall in Barry, Britain April 28, 2015. Britain will go to the polls in a national election on May 7. (Photo by Cathal McNaughton/Reuters)

U.S. President Barack Obama speaks with Japanese Prime Minister Shinzo Abe (R) as they ride together en route to the Lincoln Memorial in Washington in this April 27, 2015 handout photo. (Photo by Pete Souza/Reuters/White House)

U.S. First Lady Michelle Obama (R) greets Mrs. Akie Abe, wife of Japanese Prime Minister Shinzo Abe, at Great Falls Elementary School in Great Falls, Virginia, April 28, 2015. (Photo by Yuri Gripas/Reuters)

Governor General of Canada David Johnston tours the offices of “1871”, a hub for digital startups, in Chicago, Illinois, April 28, 2015. (Photo by Jim Young/Reuters)

An Israeli Arab wearing make-up takes part in a protest against housing shortage and house demolitions in Arab communities, in Tel Aviv's Rabin Square, Israel April 28, 2015. (Photo by Baz Ratner/Reuters)

A woman takes pictures of the artwork “Every word is like an unnecessary stain on silence and nothingness” by Spanish artist Eugenio Ampudia at Matadero Madrid culture center in Madrid, Spain, April 28, 2015. A pool of still water reflects the burnt-out beams, walls and ceiling of a burnt-out room. Matadero Madrid, located in an old slaughterhouse and livestock market, is a music, art, design and film center which opened its doors in 2007. (Photo by Susana Vera/Reuters)

An aerial view through a window of a helicopter shows smoke from forest fires in northern Ukraine, April 28, 2015. Emergency services were battling on Tuesday to prevent Ukraine's largest forest fire since 1992 from spreading towards the abandoned Chernobyl nuclear power plant, Prime Minister Arseny Yatseniuk said. Earlier, the interior ministry had warned that high winds were blowing the fire in northern Ukraine towards Chernobyl, where in 1986 a reactor fire led to the world's worst nuclear disaster. A 30 km (18.6 miles) exclusion zone remains in place around the plant, which remains contaminated by radioactive particles. (Photo by Andrew Kravchenko/Reuters)

Ukraine's Prime Minister Arseny Yatseniuk (L) is seen inside a helicopter during a flight to inspect and control the forest fires situation in northern Ukraine, April 28, 2015. (Photo by Andrew Kravchenko/Reuters)

An aerial view from a helicopter shows fire on the ground in northern Ukraine, April 28, 2015. (Photo by Andrew Kravchenko/Reuters)

Sudanese President Omar Hassan al-Bashir (C) leads victory celebrations after the Sudanese Armed Forces (SAF) and the Rapid Support Forces (RSF) defeated the Justice and Equality Movement (JEM) rebels during his visit to the battle area of Gouz Dango in South Darfur April 28, 2015. (Photo by Reuters/Stringer)

Justice and Equality Movement (JEM) rebels, who were captured after being defeated by the Sudanese Armed Forces (SAF) and the Rapid Support Forces (RSF), sit during a visit by Sudanese President Omar Hassan al-Bashir to the battle area of Gouz Dango in South Darfur April 28, 2015. (Photo by Reuters/Stringer)

Members of the Sudanese Armed Forces (SAF) and the Rapid Support Forces (RSF) in rebel vehicles which they captured, wave to Sudanese President Omar Hassan al-Bashir as he arrives to lead victory celebrations after they defeated the Justice and Equality Movement (JEM) rebels in the Gouz Dango area in South Darfur April 28, 2015. (Photo by Reuters/Stringer)

Dancers perform before the arrival of WBC/WBA welterweight champion Floyd Mayweather Jr. at MGM Grand Garden Arena on April 28, 2015 in Las Vegas, Nevada. Mayweather will face WBO welterweight champion Manny Pacquiao in a unification bout on May 2, 2015 in Las Vegas. (Photo by Ethan Miller/Getty Images)

Slovakia's Member of the European Parliament Monika Flasikova Benova holds a leaflet with the slogan “I am a migrant” as she arrives to attend a debate on the latest tragedies in the Mediterranean and E.U. migration and asylum policies at the European Parliament in Strasbourg, France, April 29, 2015. (Photo by Vincent Kessler/Reuters)

Members of the European Parliament hold leaflets with the slogans “I am a migrant” and “Europe sinking shame” at the end of a debate on the latest tragedies in the Mediterranean and E.U. migration and asylum policies at the European Parliament in Strasbourg, France, April 29, 2015. (Photo by Vincent Kessler/Reuters)

Alpha, who said he is a migrant from the border of Mauritania and Senegal arranges his shelter in the makeshift camp near the Jules Ferry center for migrants, on the outskirts of Calais, northern France, Wednesday, April 29, 2015. Many migrants have settled outside Calais near the Jules Ferry migrants supply center. (Photo by Francois Mori/AP Photo)

Visitor looks at an art installation on the wall inside a bunker in Konjic, Bosnia and Herzegovina, April 24, 2015. A group of Bosnian artists plan to turn the former atomic-bomb bunker, once the best kept secret of socialist Yugoslavia, into a vast museum dedicated to the Cold War. (Photo by Dado Ruvic/Reuters)

Female Kurdistan Workers Party (PKK) fighters leave to join others at a position which had been hit by Islamic State car bombs in Sinjar, March 11, 2015. Women fighters at a Kurdistan Workers Party (PKK) base on Mount Sinjar in northwest Iraq, just like their male counterparts, have to be ready for action at any time. Smoke from the front line, marking their battle against Islamic State, which launched an assault on northern Iraq last summer, is visible from the base. Many of the women have cut links with their families back home; the fighters come from all corners of the Kurdish region. (Photo by Asmaa Waguih /Reuters)

A female Kurdistan Workers Party (PKK) fighter sleeps at a base in Sinjar, March 11, 2015. (Photo by Asmaa Waguih /Reuters)

A female Kurdistan Workers Party (PKK) fighter stands near a security position in Sinjar, March 13, 2015. (Photo by Asmaa Waguih /Reuters)

Afghan National Army soldiers fire artillery during a battle with Taliban insurgents in Kunduz, Afghanistan, April 29, 2015. The U.S. military has sent fighter jets to Afghanistan's northern province of Kunduz, where Taliban insurgents have launched a major offensive and overrun government checkpoints close to the main city, U.S. and Afghan sources said. (Photo by Reuters/Stringer)

Democratic presidential candidate Hillary Clinton greets a supporter following her address at the 18th Annual David N. Dinkins Leadership and Public Policy Forum at Columbia University in New York April 29, 2015. (Photo by Brendan McDermid/Reuters)

Models use their smartphones backstage prior to a fashion show by Lebanese designer Abed Mahfouz during Spring-Summer 2015 in Beirut April 29, 2015. (Photo by Alia Haju/Reuters)

A model displays a creation by Lebanese designer Abed Mahfouz during the Spring-Summer 2015 fashion show in Beirut, April 29, 2015. (Photo by Alia Haju/Reuters)

A model poses during the Spring-Summer 2015 fashion show for Lebanese designer Abed Mahfouz in Beirut, April 29, 2015. (Photo by Alia Haju/Reuters)

A model displays a creation by Lebanese international designer Abed Mahfouz during his Spring-Summer 2015 fashion show in Beirut, Lebanon, Wednesday, April 29, 2015. (Photo by Hussein Malla/AP Photo)

A model, left, takes a picture of her colleague, right, in the backstage as they prepare to display creations by Lebanese international designer Abed Mahfouz during his Spring-Summer 2015 fashion show in Beirut, Lebanon, Wednesday, April 29, 2015. (Photo by Hussein Malla/AP Photo)

A model displays a creation by Lebanese international designer Abed Mahfouz during his Spring-Summer 2015 fashion show in Beirut, Lebanon, Wednesday, April 29, 2015. (Photo by Hussein Malla/AP Photo)

A pair of militia members prepare to fly drones during a test in Shanghai, China, April 21, 2015. China is stepping up research into military drones as its arms industry looks to increase export volumes, hoping to gain traction with cheaper technology and a willingness to sell to countries Western states are reluctant to. (Photo by Reuters/Stringer)

An aerial view of the construction site of the Rio 2016 Olympic Velodrome venue at the Rio 2016 Olympic Park in Rio de Janeiro February 26, 2015. Brazil's Ministry for Labor said on April 29, 2015 it stopped construction work at two venues – the tennis arena and the velodrome – being built for the Olympic Games in Rio de Janeiro next year due to health and safety concerns. (Photo by Ricardo Moraes/Reuters)

Dancers of the Morena Celarie National Dance Academy perform during the celebration of International Dance Day in San Salvador April 29, 2015. International Dance Day, which was introduced in 1982 by the Dance Committee of the International Theatre Institute, falls annually on April 29 and is a celebration of the art form. (Photo by Jose Cabezas/Reuters)

A woman prays under lotus lanterns that have been tagged with prayer petitions and names, in preparation for the upcoming birthday of Buddha at Jogye temple in Seoul, South Korea, April 30, 2015. Buddha's birthday is celebrated on May 25 in South Korea. (Photo by Kim Hong-Ji/Reuters)

People pose next to a police vehicle during the Expo Seguridad Mexico 2015 security fair in Mexico City April 29, 2015.The exhibition, which runs until April 30, presents the latest in police, civil defence and security equipment. (Photo by Henry Romero/Reuters)

Descendants of American Southerners wearing Confederate-era dresses and uniforms dance during a party to celebrate the 150th anniversary of the end of the American Civil War in Santa Barbara D'Oeste, Brazil, April 26, 2015. The U.S. Civil War ended 150 years ago, but once a year, deep in the sugar cane fields of southern Brazil, the Confederate battle flag rises again. It would be an unlikely scene in the United States, where many consider the flag a symbol of racism, slavery and segregation. Public outcry over those connotations have led to the steady withdrawal of the flag from public display in recent years. In Brazil, though, the banner is an integral part of the Festa Confederada, an annual gathering to celebrate the history of the roughly 10,000 Confederates who migrated to this South American country after their side lost the war. (Photo by Paulo Whitaker/Reuters)

Singer Lucero arrives at the 2015 Latin Billboard Awards in Coral Gables, Florida April 30, 2015. (Photo by Joe Skipper/Reuters)

TV host Jorge Bernal shoots a selfie with a Latin Billboard award during the Latin Billboard Awards Thursday, April 30, 2015, in Coral Gables, Fla. Bernal did not win an award. (Photo by Alan Diaz/AP Photo)

Jennifer Lopez hugs Suzette Quintanilla and A.B. Quintanilla, siblings of slain slinger Selena, during the Latin Billboard Awards Thursday, April 30, 2015, in Coral Gables, Fla. Lopez performed with Selena's band, which included the two siblings. (Photo by Lynne Sladky/AP Photo)

Singer Natalia Jimenez accepts an award at the 2015 Latin Billboard Awards in Coral Gables, Florida April 30, 2015. (Photo by Carlo Allegri/Reuters)

Singer Isabella Castillo arrives at the 2015 Latin Billboard Awards in Coral Gables, Florida April 30, 2015. (Photo by Joe Skipper/Reuters)