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)

These stunning images document the everyday lives of the men, women and children of the Mentawai tribe. The Mentawai people, a native population in Indonesia, are famous for their decorative tattoos and for living a semi-nomadic life on the Mentawai Islands in West Sumatra. Shot by professional photographer Mohammed Saleh Bin Dollah, the series captures a glimpse of life on the island as the Mentawai men smoke and hunt for food and the children play in the river. Here: A young boy helps a woman to prepare food taken on July 19, 2014 on the Mentawai Islands, Indonesia. (Photo by Muhamad Saleh Dollah/Barcroft Media)

Honda MotoGP rider Dani Pedrosa (R) of Spain sprays champagne on an attendant next to Yamaha MotoGP rider Valentino Rossi (C) of Italy after winning the Japanese Grand Prix at the Twin Ring Motegi circuit in Motegi, north of Tokyo, Japan, October 11, 2015. Rossi placed second. (Photo by Issei Kato/Reuters)

Actors perform the living Nativity biblical scenes in Postojna cave in Postojna, Slovenia, December 22, 2015. (Photo by Srdjan Zivulovic/Reuters)

An employee of German car manufacturer Mercedes Benz adjusts the brand's characteristic star on a GLA model at their production line at the factory in Rastatt, Germany, January 22, 2016. (Photo by Kai Pfaffenbach/Reuters)

A British Airways passenger plane flies in front of the moon above London, Britain, May 3, 2018. (Photo by Toby Melville/Reuters)

A resident walks on a makeshift walkway above a flooded street from the rising Rio Solimoes, one of the two main branches of the Amazon River, in Careiro da Varzea of Amazonas State, Brazil, June 30, 2015. According to the state Civil Defense, more than 460,000 people were affected by strong rains in the state. (Photo by Bruno Kelly/Reuters)

These stunning images show the phwoar-some power of some of Americas most extreme weather. Camille Seaman’s wondrous work features huge super cells, crashing lightning and gale-force winds. The roaming photographer has chased storms across the US from Iowa to Wyoming and from Minnesota to Texas. Her favorite places to chase are Kansas, Nebraska and South Dakota – notorious hotspots for spectacular storms. Here: Supercell in Minnesota, near Browerville, Minnesota in 2014. (Photo by Camille Seaman/Caters News)