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)

This photo taken on April 4, 2021 shows migratory birds flying over a wetland near the Yalu River in Dandong, in China's northeastern Liaoning province. (Photo by AFP Photo/China Stringer Network)

In the works of a photographer named Dave – who goes by Freaktography and never gives out his full name – haunting abandonment leaps from images of discarded machinery, tools and factory essentials. (Photo by Freaktography/Caters News Agency)

Central Palo Seco power station of the Puerto Rico Electric Power Authority (PREPA) is seen behind a cemetery, in San Juan, Puerto Rico on January 22, 2018. (Photo by Alvin Baez/Reuters)

Migratory flamingos arriving from Europe are seen in Port Fouad Nature Reserve, on the outskirts of Port Said Governorate, Egypt on December 12, 2022. (Photo by Mohamed Abd El Ghany/Reuters)

A girl rides a donkey as another walks by at the Shawqaba camp for internally displaced people who were forced to leave their villages by the war in Yemen's northwestern province of Hajjah March 12, 2016. In northwest Yemen, one of the poorest countries in the Middle East, about 400 families uprooted by the war have been stuck in the Shawqaba camp in Hajjah province for the past year. Residents live in poorly built huts that protect them neither from summer heat nor winter cold in a camp that lacks the most basic services. (Photo by Abduljabbar Zeyad/Reuters)

A man rides his loaded tricycle next to three schoolgirls in Shanghai on December 11, 2015. (Photo by Johannes Eisele/AFP Photo)

A man poses for a picture to show his rings of gold, silver and bronze on his fist in Zamfara, Nigeria April 21, 2016. (Photo by Afolabi Sotunde/Reuters)