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)

A view of one of the dioramas contained inside iron boxes as part of the “S.A.C.R.E.D” installation by Chinese artist Ai Weiwei during a media preview at the cathedral in Cuenca, Spain, July 21, 2016. Ai Weiwei has reproduced scenes of his incarceration for a new art installation, a series of almost life-size dioramas – encased in steel boxes – showing his life in jail. (Photo by Susana Vera/Reuters)

Employee Victoria Livesey walks past Banksy's “Kate Moss 2005” on display at Bonhams on March 23, 2012 in London, England. The painting, estimated at GBP 30,000 – 50,000, USD 48,000 – 79,000 and 35,000 – 59,000 euros forms part of the Urban Art Sale, which takes place at Bonhams on March 29, 2012. (Photo by Peter Macdiarmid/Getty Images)

“Pieter Hugo was born 1976 and grew up in Cape Town, South Africa. He is a South African photographer who primarily works in portraiture and whose work engages with both documentary and art traditions with a focus on African communities. His most recognized work is the series called “The Hyena & Other Men” and which was published as a monograph. It has received a great deal of attention. Hugo won first prize in the Portraits section of the World Press Photo 2005 for a portrait of a man with a hyena”. – Wikipedia

Photo: Abdullahi Mohammed with Mainasara, Ogere-Remo, Nigeria 2007. (Photo by Pieter Hugo)

Mike De Butts adds the finishing touches to a giant Baobab Tree sculpture entitled “Under the Baobab”, outside the Southbank Centre on May 24, 2012 in London, England. The Pirate Technics' installation is made from a selection of brightly coloured fabrics from around the world, and is part of the Southbank Centre's “Festival of the World” exhibition, which includes a series of large scale pieces of art that will be in place around the Southbank centre over the Summer. (Photo by Dan Kitwood)

One hundred artists were given an opportunity to uniquely redesign 100 phone booths in São Paulo. The result is beyond all expectations. One hundred completely useless or just vandalized booths were transformed into incredible works of art.

Work: Live Connected
Artist: Juarez Fagundes
Address: Avenida Paulista, Parque Trianon – opposite the park

People are often fascinated by things that baffle them. For example, Livia Marin creates porcelain pottery that looks as if it has partially melted. This pottery might serve little purpose, yet it is definitely a curious thing to have in your house. This set of pictures shows off her “Nomad Patterns” series of deformed vases, pitchers, and teacups. The most appealing thing about these pieces of art is that the patterns on the “melted” parts are as beautiful as on the rest of the pottery. (Photo by Livia Marin)

All throughout history of mankind people were fascinated by time, its flow, and how to measure it. Thus, the science of horology can into being, as people invented more and more sophisticated ways of measuring the passage of time. Truly, it’s one of the most profound characteristics of being a human, to feel and to ponder the meaning of time, its properties, and will we ever be able to move through it, not with it. Now, however, horology is mainly referred to the art of mechanical watchmaking. (Photo by MB&F)