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)

Mirko Hanák was born in 1921 in Prague, Czech Republic and worked as a painter, graphic designer and illustrator. His specialties were animals and human figures that were full of life and fun. He also had a firm grasp on composition as his paintings were so well balanced despite his casual fluid line. He was working on “Charlotte's Web” the movie when he tragically died at the height of his career from leukemia in 1971.

In this February 7, 2014 file photo, Matt Figi hugs and tickles his once severely-ill seven year old daughter Charlotte, as they walk together inside a greenhouse for a special strain of medical marijuana known as Charlotte's Web, which was named after the girl early in her treatment for crippling severe epilepsy, in the mountains west of Colorado Springs, Colo. Colorado is poised to award more than $8 million for medical marijuana research, a step toward addressing complaints that little is known about pot's medical potential. Among the research projects poised for approval on Wednesday, December 17, 2014, are one for pediatric epilepsy patients, and another for children with brain tumors. (Photo by Brennan Linsley/AP Photo)

The photography duo of Floto+Warner created the series, “Colorant”, from an idea that stemmed out of a previous series and the fascination of landscapes, with results that leave one in awe. Creating shapes, not experienced in nature, they tossed colored water in the air to capture “a momentary graffiti of air and space”. Using a high shutter speed to capture these fleeting moments, Floto/Warner has produced a multi-medium series with jaw-dropping results. Photo: “Orange Salt Flats”. (Photo by Floto/Warner)

With their affinity for hunting, sneaking, and hidden blade-like retractable claw, cats are really the assassins of the animal world. They're not as intimidating when they're kittens dressed up as assassins from the upcoming Assassin's Creed Unity, but what they lack in deadliness they more than make up for in cuteness. YouTube user Mr.TVCow posted the video, in which four hooded kittens hunt down a french soldier, much like like in a number of trailers for Assassin's Creed Unity. They use their eagle vision ability, parkour after their target, and perform lethal aerial assassinations, and yes, it's as unbearably adorable as it sounds.

A surfer rides a wave at the snowy beach of Unstad, in Lofoten Island, Arctic Circle, on March 9, 2016. Surfers from all over the world comes to Lofoten island to surf in extrem conditions. Ocean temperature is 6-7 °C, air temperature around 0°C in spite of a weather very unstable. (Photo by Olivier Morin/AFP Photo)