9Odessa Catacombs in Odessa

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With more than 1,500 miles of tunnels under this city in Ukraine and its surrounding regions, this was said to be used in limestone mining but there was more to this story, according to reports. Touted to be larger than the catacombs in London and Paris, this place is forbidden to be entered but still, curious teenagers and urban explorers just could not resist going inside. Click the next ARROW to see the next image!