Yes, there are some aspects in real life that can be related to 'Attack on Titan'. For example, the theme of survival against a seemingly overwhelming threat can be seen in various historical events like sieges where a small group of people had to defend against a much larger and menacing force. Also, the idea of living within enclosed spaces for protection has historical precedents, such as walled cities in medieval times.
Sort of. The concept of a society living in a restricted area and being afraid of the unknown outside can be compared to some isolated communities in real life. Some tribes in remote areas might be cut off from the outside world due to geographical barriers and might have their own fears and superstitions about what lies beyond their known territory, similar to how the people in the 'Attack on Titan' world view the Titans outside the walls.