A young boy plugs his ears as his sister (C) and nanny (L) watch from Gravelly Point Park as planes land at Reagan National Airport in Arlington, Virginia on June 29, 2017. President Donald Trump' s travel ban on people from six mostly Muslim countries will come into force late Thursday, as controversy swirls over who qualifies for an exemption based on family ties. (Photo by Jim Watson/AFP Photo)

Two female revelers engage in a beer drinking contest in the Hacker Pschorr tent on the first day of the 2017 Oktoberfest beer fest on September 16, 2017 in Munich, Germany. Oktoberfest is the world's largest beer celebration and typically draws over six million visitors over its three-week run. Oktoberfest includes massive beer tents, each run by a different Bavarian brewer, as well as amusement rides and activities. (Photo by Philipp Guelland/Getty Images)

Taronga Zoo's elephant baby, as yet unnamed, is seen at Taronga Zoo on March 12, 2010 in Sydney, Australia. The Asian Elephant calf has continued to make progress following a protracted labour that spanned six days. The calf was originally believed to have died in the womb during labour but surprised veterinarians and zoo staff with an unexpected delivery early Wednesday morning. (Photo by Bobby-Jo Vial/Taronga Zoo via Getty Images)

A 6-week old Fennec fox, the smallest species of foxes, and a native to the Sahara desert in Africa, looks as its mother eats in the Ramat Gan Safari Park near Tel Aviv, Israel, Sunday, November 6, 2016. Sagit Horowitz, the safari spokeswoman said four Fennec foxes were born about six weeks ago. (Photo by Ariel Schalit/AP Photo)

People remove mud and rocks from their house after a massive landslide in Chosica, March 24, 2015. Seven people were killed and more were feared dead in Peru after a massive landslide buried parts of a town amid heavy rains, authorities said on Tuesday. Six were missing and 25 injured in the disaster in Chosica, some 30 kilometers (18.6 miles) east of Lima, said Alfredo Murgueytio, the head of the National Civil Defense Institute, Indeci. (Photo by Mariana Bazo/Reuters)

In this photo released by Xhinhua News Agency, a rescuer evacuates residents near the site of a chemical plant blast in Zhangzhou, southeast China's Fujian Province Tuesday, April 7, 2015. Six people have been hospitalized and hundreds of firefighters deployed to battle a blaze sparked by an explosion at Goure PX Plant that produces the toxic chemical paraxylene, officials said Tuesday. (Photo by Wei Peiquan/AP Photo/Xinhua)

A women rides a motor bike on a street covered with volcanic ash from an eruption of Mount Kelud, in Solo, Indonesia, Friday, February 14, 2014. A major volcanic eruption in Indonesia blasted clouds of ash and debris 18 kilometers (12 miles) into the air on Friday, forcing authorities to close six airports, cancel flights elsewhere in Southeast Asia and evacuate more than 100,000 people from the mountain. (Photo by Hafidz Novalsyah/AP Photo)

Visitors walk past the fully equipped dining table inside the “Crazy House”, which is completely built upside-down, in the village of Affoldern near the Edersee lake, May 7, 2014. Three friends came up with the idea to build the tourist attraction, which cost about 200,000 euros and took some six weeks to complete. (Photo by Kai Pfaffenbach/Reuters)