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)

Race goers are pictured during the Investec Ladies Day at Epsom Downs Racecourse on June 2, 2017 in Epsom, England. (Photo by News Group Newspapers Ltd)

Personal trainer Antonietta Orsini carries out an exercise class for her neighbours from her balcony while Italians cannot leave their homes due to the coronavirus disease (COVID-19) outbreak, in Rome, Italy, March 18, 2020. (Photo by Remo Casilli/Reuters)

The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

A man walks near a tree unrooted by high winds brought by Super Typhoon Saola in Causeway Bay in Hong Kong on September 1, 2023. Super Typhoon Saola threatened southern China on September 1 with some of the strongest winds the region has endured, forcing the megacities of Hong Kong and Shenzhen to effectively shut down. (Photo by Mladen Antonov/AFP Photo)

Fish are thrown onto a truck during a winter fishing festival held on the frozen Wulungu Lake in Fuhai county, Xinjiang Uighur Autonomous Region, January 18, 2015. (Photo by Reuters/China Daily)

Japanese sеx doll exhibition attracts hundreds of mannequin-fetishists to celebrate 40 years of the X-rated love bots in Tokyo, Japan on May 19, 2017. These silicon seductresses were the star of an extraordinary exhibition in Japan showcasing sеx dolls that cost as little as a second hand car. Japanese sеx doll maker Orient Industry (originally Orient made dolls for disabled people) were laying bare their dazzling bevvy of beauties in an extravaganza to mark its 40th anniversary this week. Here: Orient industry prides itself on its detail with two looking extremely real as they sit flirtatiously on a couch. (Photo by Masatoshi Okauchi/Rex Features/Shutterstock)

“Amphilophus citrinellus is a large cichlid fish endemic to the San Juan River and adjacent watersheds in Costa Rica and Nicaragua. In the aquarium trade A. citrinellus is often sold under the trade name of Midas cichlid. A. citrinellus are omnivorous and their diet consists of plant material, molluscs and smaller fish”. – Wikipedia

Photo: Two Midas Cichlid (lat: amphilophus citrinellus) fish are seen in an aquarium at Hellabrunn zoo on December 23, 2009 in Munich, Germany. (Photo by Alexandra Beier/Getty Images)