In this August 21, 2017 photo released by the U.S. Defense Department, Qatari special operations personnel conduct a military free-fall Friendship Jump over Qatar. The U.S. military has halted some exercises with its Gulf Arab allies over the ongoing diplomatic crisis targeting Qatar, trying to use its influence to end the monthslong dispute, authorities told The Associated Press on Friday, October 6, 2017. (Photo by Staff Sgt. Trevor T. McBride/ U.S. Air Force via AP Photo)

The buildings of the banking district are seen through thousands of rain drops on a glass railing in central Frankfurt, Germany, Wednesday, January 11, 2017. (Photo by Michael Probst/AP Photo)

A baby tamandua, or anteater, named Poco sticks out its tongue on May 31, 2018. ZSL London Zoo is celebrating the creature’s surprise birth after they found a male to be the companion of its mother Ria last October. (Photo by ZSL London Zoo/PA Wire)

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)

Members of the Coney Island Polar Bear Club warm up before swimming at the beach at Coney Island in New York, December 15, 2013. (Photo by Eric Thayer/Reuters)

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)

Labrador puppies “Hoey” (L) and “Hatton”, named in honor of September 11, 2001 attack victims Patrick Hoey and Lenny Hatton who died in the World Trade Center, are pictured on the grounds of the Pentagon near Washington, June 28, 2011. (Photo by Jason Reed/Reuters)

Senator Barack Obama (D-IL) (R) stands in front of Senator Hillary Clinton (D-NY) as they arrive for U.S. President George W. Bush's annual State of the Union speech to a joint session of Congress at the U.S. Capitol in Washington in this January 23, 2007 file photo. Hillary Clinton announced her second run for the presidency on April 12, 2015 starting her campaign as the Democrats' best hope of fending off a crowded field of lesser-known Republican rivals and retaining the White House. (Photo by Larry Downing/Reuters)