A trader speaks on the phone at his desk at the Frankfurt stock exchange, Germany, in this June 29, 2015 file photo. Federal Reserve policymakers are widely seen raising interest rates for the first time in almost a decade at their next meeting this week. (Photo by Ralph Orlowski/Reuters)

In this Sunday, May 29, 2016 photo, fighters take a selfie while firing artillery during fight against Islamic State militants in Fallujah, Iraq. Iraqi forces this week pushed into the city's southern sections after securing surrounding towns and villages more than 50,000 people are believed to be trapped inside the Sunni majority city, about 65 kilometers (40 miles) west of Baghdad. (Photo by Anmar Khalil/AP Photo)

Playboy Bunny, Penny (surname not given), is helped into her costume as she prepares herself before starting work at the Playboy Club on July 26, 2016 in London, England. The Playboy Club London is celebrating its 50th anniversary this year and will mark the event with a “Touch of Gold” party on July 29. (Photo by Carl Court/Getty Images)

A layer of morning mist still covers the fields as the sun rises into the morning sky over Hohenfelden, Thuringia state, Germany, early 07 September 2016. Meteorologists predict the weather to become warm and sunny in the region with temperatures reaching around 256 degrees Celsius. (Photo by Martin Schutt/EPA)

A man poses in front of a portrait of late Chinese Chairman Mao Zedong during the opening of an exhibition of Mao related art in Beijing, China, September 8, 2016. (Photo by Thomas Peter/Reuters)

A picture made available on 08 July 2015 showsa lightning strikes during a heavy storm over Poznan in the night of 07 July 2015. Severe storms passed last night over Poland causing lots of damages to buildings, trees, electricity and railway tractions. (Photo by Lukasz Ogrodowczyk/EPA)

A picture made available on 17 July 2015 shows the bright line of the Milky Way above the old oaks at the Rogalin landscape Park in Rogalin village, near Poznan, on the night of 16 July 2015. (Photo by Lukasz Ogrodowczyk/EPA)

Competitors climb in front of the Matterhorn mountain at the start of the 21st Glacier Patrol race in Stafel outside the ski resort of Zermatt, Switzerland, 18 April 2018. The Glacier Patrol (Patrouille des Glaciers in French), organized by the Swiss Army, takes place from April 17 to 21. Highly-experienced hiker-skiers trek for over 53km (3994m ascent and 4090m descent) along the Haute Route along the Swiss-Italian border from Zermatt to Verbier. (Photo by Valentin Flauraud/EPA/EFE)