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)

Pedestrians have a snowball fight in Times Square following a mandatory shutdown of the streets at 11 p.m. on January 26, 2015 in New York City. New York, and much of the Northeast, is bracing for a major winter storm which is expected to bring blizzard conditions and 10 to 30 inches of snow to the area. (Photo by Alex Trautwig/AFP Photo)

An Israeli soldier prays in front of a tank at a military staging area near the border with the Gaza Strip, in this July 24, 2014 file photo. Israel's long-running struggle to balance modern standards with Jewish tradition has come to a head in the military, where new orders curtailing beards among soldiers have met protests from some rabbis. (Photo by Nir Elias/Reuters)

A man looks at a mural painted on the walls of houses in Zaraeeb, created by French-Tunisian artist El Seed, in the shanty area known also as Zabaleen or “Garbage City” on the Mokattam Hills in eastern Cairo, Egypt, April 4, 2016. (Photo by Amr Abdallah Dalsh/Reuters)

An Iraqi military vehicle passes displaced Iraqi boys returning to their homes in West Mosul's Oreibi neighbourhood after government forces retook control of the area from the Islamic State (IS) group during the ongoing offensive against the jihadists on May 21, 2017. (Photo by Ahmad Al-Rubaye/AFP Photo)

A cosplayer poses for a photograph during the Tokyo Rainbow Pride Parade on May 6, 2018 in Tokyo, Japan. The LGBT community and supporters marched down Shibuya and Harajuku areas on the final day of the Tokyo Rainbow Pride 2018 event. (Photo by Tomohiro Ohsumi/Getty Images)

Fishermen are seen near thousands of fish found dead at Lake Maninjau due to lack of oxygen levels at the bottom of the lake and bad weather that hit the area in Agam, West Sumatra Province, Indonesia on April 29, 2021. (Photo by Muhammad Arif Pribadi/Antara Foto via Reuters)

Smoke billows from the Mt Etna volcano as seen from Linguaglossa, Sicily on Monday, August 9, 2021. Europe's most active volcano remains active scattering ashes around a vastly populated area on its slopes. (Photo by Marco Restivo/Barcroft Media via Getty Images)