Hikers walk to reach the top of Naqba Rum area in South Sinai, Egypt, November 20, 2015. Bedouins in the "Sinai is Safe" group guided more than 100 hikers over a 25 km (15 mile) trek over the trails of the White Canyon and the Closed Canyon. The NGO aims to challenge mainstream perceptions of the area by encouraging Nile Valley residents to explore the untamed wilderness with the Bedouin tribes. (Photo by Asmaa Waguih/Reuters)

Greyhounds compete during a race at Santiago city, March 8, 2014. With over 100 years of history, greyhound racing attracts people mainly from rural areas of Santiago every weekend. Some dogs come from Argentina, the United States and Ireland and can develop a speed of up to 80 kilometers per hour on a straight running track of about 200 meters, according to organisers. Bets range from $2 to $1,000 per race, offering a livelihood for breeders and gamblers. (Photo by Ivan Alvarado/Reuters)

Students hold their weapons before the swearing in ceremony for the military students, in Bucharest, Romania, Wednesday, October 25, 2017. The Romanian Army is proudly celebrating their Army Day and marking 100-years since the landmark battle of Marasesti, a key World War I battle in 1917 when Romanian and Russian soldiers defeated German troops, halting a German offensive. (Photo by Vadim Ghirda/AP Photo)

This 1931 Stutz DV-32 convertible sedan has 66,000 miles on its odometer and its original leather luggage awaits its first complete restoration Tuesday, March 5, 2013 at L'Cars Automotive Specialties in Cameron, Wis. The company which does high-end restoration and customization work classic cars that have won awards at the world-renowned Pebble Beach Concours d'Elegance. Winning cars include a 57c Bugatti, Rolls Royce PIII V12, V12 Aero coupe, T44 Bugatti, T55 Bugatti, T38A Bugatti, Mercedes Benz 290 Roadster, Rolls Royce Silver Ghost, T57 Bugatti, 1929 Duesenberg J, Mercedes Benz 540K cabriolet, Talbot Teardrop and a 1931 V16 Cadillac convertible. (Photo by Mark Hoffman)

After the success of their Superman series in 2013, the Canadian Mint debuted a new set of coins honouring the Man of Steel at this year's Fan Expo in Toronto. The collection is made up of three silver coins worth $10, $15 and $20, and a gold coin worth $100. Photo: Close-up of the $10 silver coin in the new Superman series from the Royal Canadian Mint. (Photo by The Canadian Press)

A dog dressed like of a bee is seen during the “Blocao” dog carnival in Rio de Janeiro, Brazil, Sunday, February 16, 2014. About 100 dogs have had their day at a pre-Carnival bash in Rio de Janeiro. A 10-man brass band and a singer belting out Rio's anthem song “Cidade Maravilhosa” (Marvelous City) kicked off the four-footed fest as dog owners gathered to party down with pooches on Copacabana beach Sunay. (Photo by Silvia Izquierdo/AP Photo)

A black bull sarcophagus stands at Puri Ubud during the Hindu Royal cremation – also know as the Pengabenan – for the late Anak Agung Niang Rai, mother of Gianyar Regent, Tjokorda Oka Artha Ardana Sukawati, at Puri Ubud in Gianyar Bali on August 17, 2011 in Ubud, Bali, Indonesia. Niang Rai died in a Denpasar hospital in May; her actual cremation will take place on August 18 and will involve a nine level, 24m high 'bade' or body carring tower, made by upto 100 volunteers from 14 local villages. It will be carried to the cremation by 4500 Ubud residents. (Photo by Ulet Ifansasti/Getty Images)

Beneath the Swedish capital lies an intricate web of underground train lines. More than 90 of the 100 stations in the 110km tunnel system, sometimes referred to as “the world’s longest art gallery”, have been decorated with paintings, installations, mosaics and sculptures by 150 artists since the 1950s. After spending a couple of weeks exploring arctic Norway and Sweden, London-based travel photographer Conor MacNeill headed underground to capture images of the metro stations. Here: A rainbow arcs over a girl on the platform of Stadion station. (Photo by Conor MacNeill/The Observer)