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)

Bridegrooms pose for a photograph as they attend a mass wedding ceremony at Arena Corinthians soccer stadium in Sao Paulo, Brazil, September 26, 2015. According to the event's organizers, at least 400 couples tied the knot during a mass wedding which was organized by the Department of Justice and Citizenship of the state of Sao Paulo. (Photo by Paulo Whitaker/Reuters)

Well, this is hardly a waist of time! Here’s the couple who traveled the U.S. with an LED hula hoop – taking magnificent landscape photographs as they went. The brilliantly vibrant photographs show off the lights and colors of the lit-up hula hoop – with the strikingly serene American landscapes in the background. Grant Mallory, 25, from Columbus, Ohio, took pictures of his 23-year-old fiance hula-hooping in various national parks across the United States over the course of a three month road trip in the summer of 2015. Here: Magnificent pictures taken by Grant Mallory. (Photo by Grant Mallory/Caters News)

A loved-up couple have captured the moments they shared a dip-kiss in different locations around the world. Rob, 34, and Joli Switzer, 33, from Maryland, embark on a minimum of four international holidays per year to ensure that they get their unique dip-kiss photograph. Here: Rob Switzer 34 proposed to Joli 33 whilst they were on holiday in Moscow, Russia. (Photo by Dipkiss Travels/Caters News Agency)

A couple covered with the US and the pride flags pay their tribute for the victims of a 12 June mass shooting in Orlando, Florida, USA, as they look at the Eiffel tower, illuminated in rainbow colours, in Paris, France, 13 June 2016. A total of 50 people including the suspect were killed and 53 were injured in a shooting attack at an LGBT club in Orlando, Florida, in the early hours of 12 June. The shooter was killed in an exchange of fire with the police after taking hostages at the club. (Photo by Yoan Valat/EPA)

People take pictures and Buddhist monk chants as a groom and a bride lay inside a pink coffin during their wedding ceremony at Wat Takien temple in Nonthaburi province, on the outskirts of Bangkok February 14, 2015. Ten Thai couples laid in the pink coffin starting 9:09 AM on Saturday during the wedding ceremony organised by the Buddhist temple on Valentine's Day. Couples believe laying briefly in the coffin will get rid of bad luck and usher happiness into their lives. (Photo by Damir Sagolj/Reuters)

Denis and Nelya, both 30, from Moscow, Russia invited brown bear Stepan along to their very special ceremony. As well as witnessing the couple exchange vows, the bear also played the role of registrar at one point. Denis said: “We both knew Stepan is a very kind bear but still it is a huge, unpredictable animal so we were a bit scared, but still happy to be able to make our dream come true. It was a fantastic experience to have this photoshoot with Stepan”. (Photo by Olga Barantseva/Caters News)

These pictures reveal the crumbling ruins of the famed Grand Orient Express, now hollowed-out and almost reduced to rubble. There are only a couple of the trains, launched in 1883, left in the world. This example stands dormant in Belgium, untouched from its last voyage in the winter of 2009. Rusty ceilings, moth-eaten seats and tattered floors capture its level of decay. A Rotterdam-based urban photographer Brian Romeijn managed to snap these pictures while exploring the area. (Photo by Brian Romeijn/IMP Features)