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)

In this file photo taken on Saturday May 1, 1993, an elderly communist woman clutches her head as police on horseback patrol the streets in Moscow. When Alexander Zemlianichenko started working as an AP photographer in Moscow, the Soviet Union was nearing its demise. (Photo by Alexander Zemlianichenko/AP Photo)

A Free Syrian Army (FSA) fighter reacts as he mourns near the body of his brother, who was an FSA fighter and died during an offensive against Islamic State fighters to take control of Qabasin town, on the outskirts of the northern Syrian town of al-Bab, Syria January 10, 2017. (Photo by Khalil Ashawi/Reuters)

Serbia's Milica Mijatovic falls during the Women's World Cup Group H qualifying soccer match between Serbia and Germany at Sports Center of FA of Serbia stadium in Stara Pazova, near Belgrade, Serbia, Tuesday, April 12, 2022. (Photo by Darko Vojinovic/AP Photo)

Elena Ivanov, visiting from San Jose, Calif., walks across the field covered poppies in full bloom near the Antelope Valley California Poppy Reserve in Lancaster, Calif., Wednesday, March 30, 2022. (Photo by Jae C. Hong/AP Photo)

Oscars “Super Fan” Vivianne Robinson wearing Hollywood-themed attire, is pictured near the red carpet arrivals area, ahead of the 95th Academy Awards, in Hollywood, California, on March 10, 2023. The red carpet for the Oscars airing on March 12, 2023, is champagne-color for 2023. (Photo by Stefani Reynolds/AFP Photo)

Ukrainian service man Oleksandr of 24th brigade stands guard at his position in the trenches at the frontline, amid Russia?s attack on Ukraine near Niu York, Donetsk region, Ukraine on April 4, 2023. (Photo by Kai Pfaffenbach/Reuters)

People take pictures near a Soviet flag flying on an embankment in Saint Petersburg, Russia on June 17, 2023. The flags of Russia, the USSR, and the Russian Empire were installed on the shore to mark the anniversaries of each flag's adoption. (Photo by Anton Vaganov/Reuters)