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 Soyuz 2.1b rocket with a Fregat-M booster and meteorology and emergency communications satellite Arktika-M No 1 launches from Baikonur Cosmodrome in Baikonur, Kazakhstan on February 28, 2021. Arktika-M No 1 is the first of ten Arktika satellites to be launched by Roscosmos into orbit. (Photo by Roscomos/TASS)

Polish boys and girls throw water over each other on “Smigus-dyngus” (or Wet Monday) during the Easter Monday in Szczecin, northwestern Poland, 18 April 2022. Smigus-dyngus is a Roman Catholic celebration held on Easter Monday in Poland. Traditionally, boys throw water over girls, this is accompanied by a number of other rituals, such as making verse declarations and holding door-to-door processions. (Photo by Marcin Bielecki/EPA/EFE)

A person in costume is pictured during the annual Easter Parade and Bonnet Festival on 5th Ave in Manhattan, New York City, U.S., April 17, 2022. (Photo by Andrew Kelly/Reuters)

A woman dances during a rehearsal by the group “Tambores de Olokun” in Rio de Janeiro, Brazil, Sunday, April 17, 2022. The Brazilian municipalities of Rio de Janeiro and Sao Paulo postponed the traditional parades of the carnival samba schools to April 22 - 23, as a result of the COVID-19 pandemic. (Photo by Bruna Prado/AP Photo)

An activist of People for the Ethical Treatment of Animals (PETA) stands along a road wearing a coat with baby dolls to raise awareness about the leather industry, in Hyderabad, India on May 6, 2022. (Photo by Noah Seelam/AFP Photo)

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)

An unmanned Antares rocket is seen exploding seconds after lift off from a commercial launch pad in this still image from video shot by Matthew Travis of Zero-G News from the press area at Wallops Island, Virginia October 28, 2014. The 14-story rocket, built and launched by Orbital Sciences Corp, bolted off its seaside launch pad at the Wallops Flight Facility at 6:22 p.m. EDT/22:22 GMT. It burst into flames moments later, then plunged to the ground in a huge ball of fire and smoke, but authorities said no one was hurt. The cause of the accident was not immediately known. (Photo by Matthew Travis/Reuters/Zero-G News)