Stunning silhouettes under European cities reveal the size and splendor of the continent’s urban foundations. Photographer and content-manager Anna Arinova, 28, from Moscow, captured the awe-inspiring labyrinths in Russia and Germany. Here: Regenwurmlager, Poland. The Regenwurmlager is an extensive underground fortification area constructed by Germany in 1920s-1940s, now in western Poland, near the city of Międzyrzecz. (Photo by Anna Arinova/Caters News)

The Supermoon rises over houses in Olvera, in the southern Spanish province of Cadiz, July 12, 2014. Occurring when a full moon or new moon coincides with the closest approach the moon makes to the Earth, the Supermoon results in a larger-than-usual appearance of the lunar disk. (Photo by Jon Nazca/Reuters)

A shopper gets caught in a heavy downpour of rain on Oxford Street, London on June 27, 2020, as sunshine and showers are forecast for much of England and Wales on Saturday, with temperatures expected to hover around 22°C (71.6F). (Photo by Dominic Lipinski/PA Images via Getty Images)

France's Romane Miradoli competes during the Women's Downhill event of the FIS Alpine Ski World Championship 2023 in Meribel, French Alps, on February 11, 2023. (Photo by Lionel Bonaventure/AFP Photo)

Olga Conover of Palm Bay, Fla., walks down the bridge at sunset carrying her merged American-Ukraine flag near the end of a march marking the one-year anniversary of Russia invading Ukraine, late Thursday afternoon, February 23, 2022, in Melbourne, Fla. A small but passionate group of Ukraine supporters took the Melbourne Causeway to show their support, organized by the Ukrainian Space Coast group. (Photo by Malcolm Denemark/Florida Today via AP Photo)

People look at a vehicle at the “Salon Prive” luxury and supercar event on June 22, 2011 in London, England. The annual three day Salon Prive offers the opportunity to view the most exotic modern and vintage super cars in the world and is being held for the first time at Syon Park. (Photo by Dan Kitwood/Getty Images)

Portugal's Patricia Mamona competes in the women's triple jump final during the Tokyo 2020 Olympic Games at the Olympic Stadium in Tokyo on August 1, 2021. (Photo by Dylan Martinez/Reuters)

Revellers enjoy themselves during Hogmanay celebrations in Edinburgh, Scotland on December 31, 2017. (Photo by Russell Cheyne/Reuters)