View of the forest fire at the Conguillo National Park, Chile, on March 24, 2015. (Photo by AFP Photo/Stringer)

In this Sunday, February 8, 2015 file photo, a man looks at a burning vehicle during a riot outside an air defense stadium in a suburb east of Cairo, Egypt. At least 22 soccer fans were crushed to death outside an air defense stadium in Cairo after police fired tear gas to break up the crowd waiting in a fenced, narrow corridor to watch. Police accused the fans of attacking the force, and rioting to enter the stadium. On Tuesday, March, 17, 2015 the chief prosecutor general also referred 16 fans to trial, accusing them of belonging to the Muslim Brotherhood. (Photo by Ahmed Abd El-Gwad/AP Photo/El Shorouk Newspaper)

In this August 16, 2013, file photo a helicopter battles a Beaver Creek Fire north of Hailey, Idaho. (Photo by Ashley Smith/The Times-News via AP Photo)

An Iranian man releases a lit lantern during Chaharshanbe Souri, or Wednesday Feast, an ancient Festival of Fire, on the eve of the last Wednesday of the solar Persian year, in Tehran, Iran, Tuesday, March 17, 2015. In Tehran, people light bonfires, set off fireworks and send wish lanterns into the night sky as part of an annual ritual that dates back to at least 1700 B.C. and is linked to Zoroastrianism. Since the 1979 Islamic Revolution, hard-liners have discouraged the celebration, viewing it as a pagan holdover from pre-Islamic times. (Photo by Vahid Salemi/AP Photo)

Partizan soccer fans light torches during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

A steel-worker is pictured at a furnace at the plant of German steel company Salzgitter AG in Salzgitter, Lower Saxony on March 17, 2015. (Photo by Fabian Bimmer/Reuters)

In this Sunday, June 30, 2013 file photo, an Egyptian protester attacks Muslim Brotherhood headquarters in Muqattam district in Cairo. Egypt's top prosecutor on Sunday, March 29, 2015 has named 18 Muslim Brotherhood members, including leader Mohammed Badie and his deputy Khairat el-Shater, as terrorists in the first implementation of an anti-terror law passed earlier this year. (Photo by Manu Brabo/AP Photo)

In this July 19, 2002, file photo, Rogue River Hot Shot Chris Lyke is silhouetted against flames as he works a burn out operation on the leading edge of the Eyerly Complex fire near Sisters, Ore. (Photo by Don Ryan/AP Photo)

Dairy farmers stand by their tractors in front of a bonfire during a demonstration against the lifting of milk quotas in front of the European Parliament in Brussels on Tuesday, March 31, 2015. Dairy farmers hit the streets of Brussels to protest against the lifting European Union milk quotas amid concern the move will flood the market with surplus milk. (Photo by Virginia Mayo/AP Photo)

A Balinese man dances on the fire during the “Mesabatan Api” ritual ahead of Nyepi Day on March 20, 2015 in Gianyar, Bali, Indonesia. Mesabatan Api is held annually a day before the Nyepi Day of Silence, as it symbolizes the purification of universe and human body through fire. Nyepi is a Hindu celebration observed every New Year according to the Balinese calendar. The national holiday is one of self-reflection and meditation and activities such as working, watching television or travelling are restricted between the hours of 6 a.m. and 6 p.m. (Photo by Agung Parameswara/Getty Images)

A worker operates a barrel with molten iron at an iron foundry in Bobruisk, southeast of Minsk, March 11, 2015. (Photo by Vasily Fedosenko/Reuters)

The SLS five-segment Solid Rocket Motor undergoes a static test fire at the Orbital ATK facility in Promontory, Utah March 11, 2015. The beefed-up space shuttle solid rocket motor passed a two-minute test firing in Utah on Wednesday, a key milestone toward the debut flight of NASA's deep-space launcher in 2018, the U.S. space agency said. (Photo by Jim Urquhart/Reuters)

Employees work at a steel factory in Dalian, Liaoning province in this March 16, 2015 file picture. China's crisis-hit steel sector is calling for strong government backing for plans to ramp up foreign acquisitions, as it looks to escape weak demand-growth and soaring environmental costs at home. In a draft of a revised restructuring plan for the industry issued late last week, Beijing included a line saying it would support mills' efforts to buy assets abroad, with attention now turning to more detailed measures that could be announced later in the year. (Photo by Reuters/China Daily)

A Catholic priest and believers take part in a service on the eve of Easter Sunday in the village of Ragotna, southwest of Minsk April 4, 2015. (Photo by Vasily Fedosenko/Reuters)

Firefighters try to extinguish a fire at a petrochemical plant in Zhangzhou, Fujian province April 7, 2015. At least six people were injured after an explosion hit part of an oil storage facility on Monday at Dragon Aromatics, Xinhua reported. The fire, which had been put off, resumed at around 7:40 p.m. on Tuesday. It was later extinguished again at around 11:40 p.m., at the plant that produces paraxylene, or PX, a chemical used in making polyester fibre and plastics, state media said. (Photo by Reuters/Stringer)

The Boeoegg, a snowman made of wadding and filled with firecrackers, burns atop a bonfire in the Sechselaeuten square in Zurich April 13, 2015. As the bells of St. Peter's church chime six o'clock, the bonfire below the “Boeoegg” is set alight and mounted guildsmen gallop around the pyre to the tune of the Sechselaeuten March. The faster the head of the “Boeoegg”, the symbol of winter, catches fire and explodes, the warmer and more beautiful the summer will be. (Photo by Arnd Wiegmann/Reuters)

A police official stands guard while confiscated drugs burn inside a military base in Santo Domingo April 16, 2015. At least 1.3 tons of cocaine were burned. (Photo by Ricardo Rojas/Reuters)

A demonstrator lights a flare while protesting outside Belgian Prime Minister office during a national strike in Brussels April 22, 2015. (Photo by Yves Herman/Reuters)

A firefighter extinguishes fire as he participate in a drill simulating a fire incident near a gas compressor station belonging to Naftogaz in the village of Boyarka, outside Kiev, April 22, 2015. (Photo by Gleb Garanich/Reuters)

Demonstrators add to a bonfire during a rally named “March for the recovery of water and life”, demanding for the nationalisation of water resources, in Valparaiso April 22, 2015. (Photo by Rodrigo Garrido/Reuters)

A Baltimore firefighter attacks a fire at a convenience store and residence during clashes after the funeral of Freddie Gray in Baltimore, Maryland in the early morning hours of April 28, 2015. (Photo by Eric Thayer/Reuters)

An ultra-Orthodox Jew looks at a bonfire as he and others celebrate the Jewish holiday of Lag Ba'Omer in Bnei Brak May 6, 2015. (Photo by Baz Ratner/Reuters)

An Iranian man jumps over a bonfire during Chaharshanbe Souri, or Wednesday Feast, an ancient Festival of Fire, on the eve of the last Wednesday of the solar Persian year, in Tehran, Iran, Tuesday, March 17, 2015. (Photo by Vahid Salemi/AP Photo)

People stand by fires they lit by a relative's grave in a cemetery during an Orthodox Palm Sunday memorial for the departed in Herasti, southern Romania, early Sunday, April 5, 2015. Orthodox believers gather at midnight, light fires at the graves and share food in memory of their dead relatives. (Photo by Vadim Ghirda/AP Photo)

U.S. soldiers from the 2nd Battalion, 1st Brigade Combat Team, 3rd Infantry Division fire their M1A2 Abrams battle tank during a military exercise at the Gaiziunu Training Range in Pabrade some 60km (38 miles) north of the capital Vilnius, Lithuania, Thursday, April 9, 2015. The United States of America has been maintaining a persistent presence of rotating land forces on the ground in the Baltic States and Poland since April 2014. (Photo by Mindaugas Kulbis/AP Photo)

Hamndmade firework rockets target Panagia Erithiani church during Greek Orthodox Easter celebrations on the eastern Aegean island of Chios, Greece, late Saturday, April 11, 2015. Thousands of handmade rockets are fired every year on Great Saturday night, before the Resurrection, by locals of the two rival churches of Agios Markos and Panagia Erithiani, in the village of Vrontados. (Photo by Petros Giannakouris/AP Photo)

In this December 30, 2013 file photo, a fireball goes up at the site of an oil train derailment in Casselton, N.D. On Tuesday, March 31, 2015, Bryan Thompson, of Fargo, N.D., the engineer of the oil tanker train involved in the derailment, filed a complaint against BNSF Railway, accusing the railroad of negligence. Thompson says BNSF failed to properly inspect and maintain its equipment and failed to warn him of the dangers of hauling explosive oil tank railcars. (Photo by Bruce Crummy/AP Photo)

In this November 8, 2005 file photo, firefighters work to extinguish burning cars set on fire by rioters in Gentilly, south of Paris, France. Two young boys were electrocuted in a power substation in Clichy-sous-Bois, while hiding from police on October 27, 2005. The boys' deaths led to three weeks of nationwide riots by those who see police not as protectors but as predators. Ten years after the boys' deaths an emotional trial has exposed a still-divided France. (Photo by Michel Spingler/AP Photo)

Flint firefighters work to contain a large fire that engulfs a former strip club, once called The Body Shop, Wednesday, April 22, 2015 at the intersection of Glenwood Avenue and Asylum Street, sending a large plume of black smoke over the city of Flint. (Photo by Jake May/The Flint Journal-MLive.com via AP Photo)

The Soyuz-FG rocket booster with Soyuz TMA-16M space ship carrying a new crew to the International Space Station, ISS, blasts off at the Russian leased Baikonur cosmodrome, Kazakhstan, Saturday, March 28, 2015. The Russian rocket carries U.S. astronaut Scott Kelly, Russian cosmonauts Gennady Padalka, and Mikhail Korniyenko. (Photo by Dmitry Lovetsky/AP Photo)

The crowd watches as stunt pilots Melissa Pemberton, Jurgis Kairys and Skip Stewart of The Immortals fly past pyrotechnics as they perform at The Australian International Airshow on March 1, 2015 in Avalon, Australia. (Photo by Scott E. Barbour/Getty Images)

Relatives carry out mass cremations at nightfall 26 April 2015 of victims who perished in the devastating earthquake of 25 april, in Kathmandu, Nepal. There are now more than 3,200 confirmed dead following the 7.9 magnitutde quake. (Photo by Abir Abdullah/EPA)

This August 18, 2014 photo by St. Louis Post Dispatch photographer David Carson, a member of the St. Louis County Police tactical team fires tear gas into a crowd of people in response to a series of gunshots fired at police during demonstrations in Ferguson. (Photo by David Carson/St. Louis Post-Dispatch via AP Photo)

Penitents hold candles as they take part in a Holy Week procession in Jerez de la Frontera, Spain, Monday, March 30, 2015. Hundreds of processions take place throughout Spain during the Easter Holy Week. (Photo by Daniel Ochoa de Olza/AP Photo)

A local Japanese man holds a traditional firework housed in a bamboo tube and reinforced with hemp rope during a ceremony at the Matsudaira Toshogu Shinto Shrine, in Matsudaira village, Toyota city, Aichi province, Japan, 11 April 2015. Participants in the event, traditionally an offering to the local gods, suffer varying degrees of burns to their body. The Mikawa region of Aichi province is famed for its firework tradition and the bravery of the local men. Traditionally, Mikawa men were considered to be the finest samurai warriors. (Photo by Everett Kennedy Brown/EPA)

People perform tradition fire dance of “Pa Phen” ethic minority, which is a part of IPU sideline activitys in Dong Mo, a Vietnamese ethnic culture-tourism village, about 60km from Hanoi, Vietnam, 29 March 2015. This festival is just reserved to the young men and they are always admired and applauded by everyone. (Photo by Ha Duc Thanh/EPA)

In this photo taken on Monday, March 16, 2015, a firefighters works to contain a grass fire north of Honey Creek, Iowa. Officials say the large grass fire in western Iowa was caused by what was meant to be a controlled burn. (Photo by Mike Bell/AP Photo/The Daily Nonpareil)

Ultra-Orthodox Jewish men burn leaven in the Mea Shearim neighbourhood of Jerusalem, ahead of the Jewish holiday of Passover, April 3, 2015. Passover commemorates the flight of Jews from ancient Egypt, as described in the Exodus chapter of the Bible. According to the account, the Jews did not have time to prepare leavened bread before fleeing to the promised land. (Photo by Ammar Awad/Reuters)

A Balinese man kicks up the fire during the “Mesabatan Api” ritual ahead of Nyepi Day on March 20, 2015 in Gianyar, Bali, Indonesia. Mesabatan Api is held annually a day before the Nyepi Day of Silence, as it symbolizes the purification of universe and human body through fire. Nyepi is a Hindu celebration observed every New Year according to the Balinese calendar. The national holiday is one of self-reflection and meditation and activities such as working, watching television or travelling are restricted between the hours of 6 a.m. and 6 p.m. (Photo by Agung Parameswara/Getty Images)