A colourful sky before sunrise on Whitley Bay beach on December 21, 2015, as December could be the mildest across a large part of England since records began more than 350 years ago, forecasters have said. (Photo by Owen Humphreys/PA Wire)

Steam emerges from a cooling tower of the nuclear power plant Leibstadt near Leibstadt, Switzerland, November 18, 2014. (Photo by Arnd Wiegmann/Reuters)

Residents walk past electoral posters in Port-au-Prince, Haiti, January 28, 2017. (Photo by Andres Martinez Casares/Reuters)

An aircraft passes over houses at it lands at Heathrow Airport near London, Britain, December 11, 2015. Picture taken December 11, 2015. (Photo by Neil Hall/Reuters)

In this Saturday, Oct. 24, 2015 photo, a Lebanese Shiite supporter of Hezbollah with a tattoo on his head that reads in Arabic, “Oh Ali”, beats his chest during the holy day of Ashoura, in the southern suburb of Beirut, Lebanon. A growing number of Shiite Muslims in Lebanon are getting tattoos with religious and other Shiite symbols since the civil war in neighboring Syria broke out five years ago, fanning sectarian flames across the region. (Photo by Hassan Ammar/AP Photo)

A supercell thunderstorm develops, May 8, 2017 in Elbert County outside of Limon, Colorado. With funding from the National Science Foundation and other government grants, scientists and meteorologists from the Center for Severe Weather Research try to get close to supercell storms and tornadoes trying to better understand tornado structure and strength, how low-level winds affect and damage buildings, and to learn more about tornado formation and prediction. (Photo by Drew Angerer/Getty Images)

A woman uses her smartphone before the Chanel Cruise Collection 2015/16 fashion show at the Dongdaemun Design Plaza in Seoul, May 4, 2015. (Photo by Thomas Peter/Reuters)

A North Korean soldier kicks a pole along the bank of Yalu River near the North Korean town of Sinuiju, opposite the Chinese border city of Dandong, February 4, 2014. (Photo by Jacky Chen/Reuters)