These black-and-white photos are taken from the new book “Armoured Warfare in the First World War 1916 – 1918” by Anthony Tucker-Jones and published by Pen & Sword Military. Here: British troops hitch a ride on a Mark IV after the massed tank fleet spearheading attack at Cambrai on November 20, 1917. (Photo by Anthony Tucker-Jones/Mediadrumworld.com)

Some are in it just for the money, others to help buy a meal. Then there are those who trade for fun or to spend time among friends. Millions of investors – pensioners, security guards, high-school students – dominate China's stock markets, conducting about 80 percent of all trades. Retirees gather in brokerage houses dotted around China also to enjoy some company and savour the air conditioning on hot days. Some start as young as 13, trading from home with an eye on future careers in finance. Winning isn't guaranteed. This year, among the most turbulent in China's financial history, its stock markets more than doubled in the six months to May, only to crash amid concerns that growth in the country, which makes everything from cars to steel, is slowing faster than previously thought. (Photo by Aly Song/Reuters)

Members of the Michiana Rocketry prep a 10-foot, 450 pound porta-potty, mounted on rocket motors for launching, Saturday, December 6, 2014, from a field in Three Oaks, Mich. It made an arc and almost landed on a spectator’s pickup truck, 2,000 feet away. A group of Michiana Rocketry club members planned the project for more than two years. The club is trying to increase awareness of rocketry as a hobby and prove it’s possible to turn a porta-potty into a rocket and launch it successfully. About 30 people worked on the rocket, from engineers to sales people who lined up sponsors. (Photo by Don Campbell/AP Photo/The Herald-Palladium)

A piñata depicting TV celebrity Kim Kardashian is displayed outside a workshop in Reynosa December 6, 2014. Mexican artisan Dalton Ramirez, known in his neighborhood for creating pinatas which depict local politicians and people in the entertainment industry, jumped on the Kardashian bandwagon after the reality star was featured in a magazine showing her famous curves. The photographs in the magazine were shot by Jean-Paul Goude and recreated his iconic “Carolina Beaumont, New York, 1976”. (Photo by Daniel Becerril/Reuters)

An Orangutan named “Pacquiao” and zoo owner Manny Tangco, wearing Santa costumes, embrace in front of Brown Philippine Deer while giving school children a tour ahead of the next week's Christmas celebration Thursday, December 18, 2014 in suburban Malabon city, north of Manila, Philippines. The yearly treat is aimed at encouraging residents to be sensitive to the feelings of animals especially when exploding firecrackers for the raucous celebration. (Photo by Bullit Marquez/AP Photo)

A tattoo is displayed on the arm of a girl during Bandung Body Art Festival at in Bandung, West Java, on December 7, 2014. Upon its establishment in 2010, founders of the Bandung Body Art Festival sought to celebrate an art form that was once taboo and associated with criminals. Tattoos are now an increasingly acceptable part of Indonesia’s urban landscape, and the annual event this year continued its campaign with 45 tattoo artists offering their services for free at the Ganesha Cultural Center. (Photo by Rezza Estily/JG Photo)

Smoke rises from the sauna as Eda Veeroja walks past with birch twigs at Mooska farm near the village of Haanja December 20, 2014. Smoke saunas are usually built without chimney and have a stove that rest on boulders where firewood is burnt until the room heats up. When the smoke is gone and the room reaches the right temperature, people sit inside and whisk each other with birch twigs. The tradition of the smoke sauna in Voromaa vicinity, in the south of Estonia, is enlisted in the UNESCO representative list of the intangible cultural heritage of humanity. (Photo by Ints Kalnins/Reuters)

In this photo taken on July 19, 2014, a man looks at an excavation as an A.R.M.H., Association for the Recovery of Historical Memory, volunteer digs on the search for the body of Perfecto de Dios, in a hidden grave in Chaherrero, Spain. Across Spain, volunteer teams of archeologists, anthropologists and forensic scientists head out every year on expeditions to dig for suspected mass graves – a legacy of Spain's fascist past during the time of General Francisco Franco. (Photo by Daniel Ochoa de Olza/AP Photo)