A customer buys a box of bullits and a target of Osama Bin Laden October 3, 2001 at Blue Ridge Arsenal in Chantilly, VA. Guns sales have risen across America since the September 11th terrorist attacks. (Photo by Mark Wilson/Getty Images)

Each winter, since 2009, the transport society of Budapest decorates its trams with more than 30 000 sparkling white and blue LED lights for Christmas. If the tram drives fast, it will turn into a wagon made of spurts of lights.

An injured woman is pictured near the Blue Parrot nightclub in Playa del Carmen, Quintana Ro state, Mexico where 5 people were killed, three of them foreigners, during a music festival on January 16, 2017. A shooting erupted at an electronic music festival in the Mexican resort of Playa del Carmen early Monday, leaving at least five people dead and sparking a stampede, the mayor said. Fifteen people were injured, some in the stampede, after at least one shooter opened fire before dawn at the Blue Parrot nightclub during the BPM festival. (Photo by Victor Vargas/AFP Photo)

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)

Aquarium visitors attend a dinner party in an underwater tunnel in Tianjin, China on September 15, 2016. Tianjin Haichang Polar Ocean World opened in the city of Tianjin, southeast of Beijing, in 2010. It gives visitors a chance to see more than 150 large animals from the Arctic and Antarctic regions, including polar bears. (Photo by Feature China/Barcroft Images)

A woman uses a phone to take a “selfie” photo with cat as she stands along the barbed wire fence demarcating the “blue line” – drawn by the United Nations to mark Israel's withdrawal from southern Lebanon in 2000 – while an Israeli Merkava battle tank is deployed nearby, at a position along the border near the village of Kfar Shuba in southern Lebanon on June 11, 2023. (Photo by Mahmoud Zayyat/AFP Photo)

A visitor takes pictures with a smartphone of an artwork entitled “Blue Europe, 2015” by Chinese artist Liu Bolin, on display during the exhibition “Visible Invisible” at the Mudec Museum in Milan on May 14, 2019. Liu Bolin known as “the invisible man” for his photographic self-portraits, focused on a body-painting blending with the surrounding area. (Photo by Miguel Medina/AFP Photo)