British soldiers inspect a captured German place in the Horseguards' Parade, London during World War I in November 1914, with the London Eye in the background as a reminder of just how much has changed in the last 100 years. (Photo by Peter Macdiarmid/Getty Images)

The Spanish photographer Xavi Bou digitally combines sequential pictures of birds to create a single image, or chronophotograph, that reveals the shapes of their flight paths against Catalonian skies. His work shows the variety and beauty to be found in the daily activities of the local birds, including spiralling storks, swooping starlings and giddy swifts. Here: European herring gulls at Llobregat Delta. (Photo by Xavi Bou/Rex Features/Shutterstock)

“Mount Hua, or Hua Shan, or Xiyue located near the city of Huayin in Shaanxi province, about 120 kilometres (75 mi) east of Xi'an. It is one of China's Five Great Mountains, and has a long history of religious significance. Originally classified as having three peaks, in modern times the mountain is classified as five main peaks, of which the highest is the South Peak at 2,154.9 metres (7,070 ft)”. – Wikipedia

Photo: Trip to Xi'an 西安. (Photo by Grant Robinson)

A woman waits to hear about her sister, a teacher, following a shooting at the Sandy Hook Elementary School in Newtown, Connecticut. A man killed his mother at their home and then opened fire inside the elementary school where she taught, massacring 26 people, including 20 children, as youngsters cowered in fear to the sound of gunshots reverberating through the building and screams echoing over the intercom. (Photo by Jessica Hill/Associated Press)

An Islamic religious leader and rebel supporter (R) chant to rally rebel fighters awaiting a rumored Libyan Army advance April 11, 2011 between the crucial towns of Ajdabiyah and Brega, Libya. Rebels continued to hold the strategic town of Ajdabiyah a day after NATO air power struck army troops loyal to Libyan ruler Moammar Gaddafi nearby, helping the rebels secure the city. (Photo by Chris Hondros/Getty Images)

A cat with a “stegosaurus spine” design cut into its fur is seen next to a dog at a pet shop, in Tainan, Taiwan June 19, 2016. Lee Mei-chen, Taiwanese hairdresser turned pet groomer, shaves paw prints, lion faces and characters from Japanese brand Hello Kitty on to animal backs. The teddy bear design is one of the most complex in the furry repertoire. Photo by Tyrone Siu/Reuters)

Japan Self-Defense Force members pay their respect to unidentified earthquake victims in vehicles during a mess funeral on April 8, 2011 in Yamamoto, Miyagi Prefecture, Japan. The 9.0 magnitude strong earthquake struck offshore on March 11 at 2:46pm local time, triggering a tsunami wave of up to ten metres which engulfed large parts of north-eastern Japan, and also damaging the Fukushima nuclear plant and threatening a nuclear catastrophe. The death toll continues to rise with numbers of dead and missing exceeding 20,000 in a tragedy not seen since World War II in Japan. (Photo by Athit Perawongmetha/Getty Images)

In this photo illustration a package of Nicotine Gum, which is advertised as helping people stop smoking cigarettes, is seen on January 10, 2012 in Miami, Florida. A study published in the journal Tobacco Control on Monday, reported that the nicotine alternatives, like Nicotine Gum, have no lasting effect on people trying to quit their smoking habit. (Photo illustration by Joe Raedle/Getty Images)