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Many people visit Berlin, Germany as tourists, learning about the history of the city and experiencing what it offers today. (1)However, many people aren't aware that there's plenty to see below Berlin, as well. (2)The Berlin Unerworlds organization is hoping to change that by exploring and preserving the massive network of underground tunnels built beneath Berlin in the mid 20th century, which is estimated to stretch on all across the city. (3) Many of these tunnels have already been opened to tourists, and guides can offer historical informaion about their use and significance in Germany's history. _________, anyone hoping to see a unique side of Germany's history should plan a trip to these tunnels.