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 woman rides a donkey during a donkey race in Roum village, Jizeen countryside, southern Lebanon, August 9, 2015. (Photo by Ali Hashisho/Reuters)

Guadalajara-based artist Gonzalo Lebrija created a public art installation in the parking lot (1430 Delgany Street, Denver, CO 80202) across from the Museum of Contemporary Art Denver (MCA Denver) in the summer of 2010. The installation, entitled History of Suspended Time: Monument for the Impossible, was developed as a dual collaboration with MCA Denver's museum-wide exhibition, Energy Effects: Art & Artifacts from the Landscape of Glorious Excess, as well as Denver's inaugural 2010 Biennial of the Americas, an international event that celebrated the culture, ideas and people of the Western Hemisphere.

A painter was drawing a lion head body painting on a model during the auto show on March 15, 2015. The local 2015 auto show was held in Xuchang Stadium in Xuchang, Henan Province, China. The exhibitors tried a variety of ways for promotion and attracting people's attention. Some exhibitors were giving gifts to the people scanning their QR codes and add them onto friends list. An auto company has invited young s*x underwear models and drew body paintings on the girls. (Photo by Xu Zhongxin/Sipa Asia)

Divers swim beside millions of silverside fish at Devil's Grotto, Cayman Islands. Swimming in unison, millions of silverside fish dwarf the divers. The fish create waves of silver light as they move around the grottos that lie beneath the surface of the Caribbean Sea. These amazing photographs were captured by Belgian photographer Ellen Cuylaerts, 44, on a diving trip to the Devil's Grotto, Cayman Islands. (Photo by Ellen Cuylaerts/This is Guavo Media)

A Fulani woman fixes her head scalf on the street of Dapchi, Yobe state, Nigeria on February 27, 2018. (Photo by Afolabi Sotunde/Reuters)

Participants take pictures of themselves as others run past the Tiananmen gate during the Beijing Marathon in Beijing, China, September 17, 2016. (Photo by Damir Sagolj/Reuters)

An armed police officer checks the documents of a cyclist at a checkpoint placed to implement a curfew in the country's capital amid rising coronavirus disease (COVID-19) cases, in Caloocan City, Metro Manila, Philippines, March 16, 2021. (Photo by Eloisa Lopez/Reuters)