Dajana Djuric, 25, who has worked as a chimney sweep since the age of six, cleans a chimney in Brcko, Bosnia and Herzegovina. Dajana Djuric, believed to be the only female chimney sweep in Bosnia and Herzegovina, has to contend with perilous roofs in the depth of winter. (Photo by Dado Ruvic/Reuters)

A woman poses with a cut-out of Vladimir Putin in the “President Cafe” in Krasnoyarsk, Siberia, Russia, April 7, 2016. Dozens of photos of Vladimir Putin, from childhood to Russian President, hang on the walls of President Cafe in a working-class area of Krasnoyarsk, a city in eastern Siberia. A life-size cut-out of Putin stands by the bar. Images of U.S. President Barack Obama, as well as leaders of Germany and Britain, greet customers in the toilets. (Photo by Ilya Naymushin/Reuters)

Fish weighing over 80 kilogram is cooked in a hotpot during a food festival in Zhengzhou, Henan province, China, October 17, 2015. (Photo by Reuters/Stringer)

An officer reviews members of the honor guard as they line up before a welcoming ceremony for visiting Mozambique's President Filipe Jacinto Nyusi at the Great Hall of the People in Beijing, Wednesday, May 18, 2016. (Photo by Mark Schiefelbein/AP Photo)

In this July 25, 2015 photo, youth eat a cooked pig's head as they wait for the start of carnival in Santiago, Cuba. (Photo by Ramon Espinosa/AP Photo)

Skeletons are arranged in a bar scene as part of a competition to create Day of the Dead altars on pedestrian Regina Street in central Mexico City, Tuesday, November 1, 2016. The holiday honors the dead as friends and families gather in cemeteries to decorate their loved ones' graves and hold vigil through the night on Nov. 1 and 2. (Photo by Rebecca Blackwell/AP Photo)

American Yoga teacher Dashama poses on a Yoga-board during a preview of the 46th International Boat Fair in Duesseldorf January 16, 2015. The BOOT 2015 watersports fair, with more than 1,600 international exhibitors will run in Duesseldorf from January 17 to January 25. (Photo by Ina Fassbender/Reuters)

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)