A creature bathes at the Robolights art installation by Kenny Irwin Jr. in Palm Springs, California December 15, 2014. The installation consists of hundreds of whimsical robot and other themed sculptures created from recycled materials including golf carts, kitchen appliances and microwaved smart phones, and is open to the public each holiday season on the sprawling Irwin family property. (Photo by David McNew/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)

Russian artist Salavat Fidai is obsessed with things in miniature, and he has previously painted miniatures on pumpkin seeds and carved sculptures into the graphite tips of pencils. For this project, he's gone for something a little bit bigger, but not by much. One of Fidai's favorite painters is the legendary Vincent Van Gogh, so he decided to do a series where he recreated some of Van Gogh's famous works on matchboxes.

Thoughts. They fly through the broad expenses of our mind, floating gracefully in midair, going into the clouds, and then reemerging once again. Some are quick and furtive, others are grand and majestic. We reflect upon them as they enter our minds, and once they leave, they are usually gone for good. However, some thoughts are different. These thoughts resemble a flock of angry birds or a swarm of hungry moths that invade your mind, slowly eating away at your sanity, strength, and desire to live. Such thoughts often plague that minds of people with Obsessive Compulsive disorder. They completely occupy their time; constantly there; ever-present. With his book sculpture, Thomas Wightman was able to accurately convey the way these thoughts consume the mind, slowly building a nest within it, resisting all attempts to drive them away.

“In 2009 a monumental underwater museum called “MUSA” (Museo Subacuático de Arte) was formed in the waters surrounding Cancun, Isla Mujeres and Punta Nizuc. The project founded by Jaime Gonzalez Cano of The National Marine Park, Roberto Diaz of The Cancun Nautical Association and Jason deCaires Taylor consists of over 450 permanent life-size sculptures and is one of the largest and most ambitious underwater artificial art attractions in the world”. – UnderwaterSculpture (Photos by Jason deCaires Taylor/Intrepidacious/Kozy and Dan Kitchens)

A resident types a text message on her mobile phone, as she sits on a bench made from a tree, which is a creation by Brazilian artist Hugo Franca at Largo da Batata square in Sao Paulo March 17, 2015. Franca, a designer from Sao Paulo is working with the city to make use of fallen trees to turn them into sculpture furniture to line the city's parks, streets and plazas. Brazil's largest city was slammed by several strong storms this rainy season that brought with them heavy rain, lightning and winds as high as 90 kilometres (55 miles) per hour. (Photo by Nacho Doce/Reuters)

Workers transport a model of a dinosaur at the exhibition “World of Dinosaurs” at a former lignite surface mining area in Grosspoesna near Leipzig, central Germany, Wednesday, October 29, 2014. A 100-foot long statue of a dinosaur had to be moved Wednesday because German authorities had deemed it a safety risk. Officials feared the sculpture could cause traffic accidents by distracting drivers on a nearby highway. The reptile, one of 50 species on show in the World of Dinosaurs exhibit near Leipzig, was moved to a less conspicuous position further from the road. (Photo by Jens Meyer/AP Photo)

In this April 1, 2002, file photo, Mike Cole, of Jenkintown, Pa., right, performs a kick-flip over a trash can with his skateboard as tourists pose for photos in front of artist Robert Indiana's sculpture in John F. Kennedy Plaza, also known as Love Park, in Philadelphia. Granite slabs from Philadelphia's famed Love Park, a skateboarding mecca though for a long stretch an illegal one, are being shipped in 2017 to the city of Malmo, Sweden, nearly 4,000 miles away, for use in construction of a skate park there. (Photo by Douglas Bovitt/AP Photo)