Paradis Island (Anime)

The human activity zone (人類活動領域), or simply human territory (人類領域), is the land surrounded by the Walls Rose and Sina, and formerly Maria. It is the only remaining place in the world known to have survived the invasion of the Titans 107 years ago.

History
In the year 743, Titans appeared and annihilated the majority of the human population seemingly overnight. Through means unknown, countless Colossal Titans gathered and formed three concentric walls, which the surviving remnants of humanity would gather behind. After this, roughly 100 years of peace followed, with the Titans being unable to breach the Walls. Despite the introduction of a three-wing military system, the remnants of humanity grew complacent in their survival. A sense of contentedness with humanity remaining behind the Walls developed, with significant consideration of the outside world, and threat, being a sign of deviance.

Population
In the fall of Wall Maria, it is said that 10,000 individuals lost their lives to the Titans, and two years later approximately 250,000 individuals participated in the operation to reclaim Wall Maria, with less than 200 individuals surviving the mission. This number of people participating in the operation is said to have been 20% of humanity's population that had survived the fall. With this information, it can be said that the total population of humanity within the Walls was approximately 1,260,000 individuals before the fall, 1,250,000 immediately afterwards, and slightly less than 1,000,200 after the operation to reclaim Wall Maria.

Furthermore, based on the known dimensions of the Walls, it can be calculated that the area of human territory is approximately 723,822 km² within Wall Maria and approximately 453,646 km² within Wall Rose. Based on these calculations, it can be said that the average population density of humanity within the Walls was approximately 1.7 individuals per square kilometer before Wall Maria's fall and approximately 2.2 individuals per square kilometer after the operation to reclaim Wall Maria. However, this does not take into account whatever population density exists within each district and town within the Walls.

Military
After the building of the Walls, surviving humanity established a three-branch military with each branch serving specific functions: the Garrison, which safeguards and reinforces the three Walls; the Scout Regiment, who venture beyond the Walls into Titan territory as a means of researching the Titans; and the Military Police Brigade, which exercises control and order over the citizens of the Walls. The latter-most branch is a position of privilege available only to the top ten graduates of each yearly Cadet Corps.

Geography and Climate
The lands surrounded by the three Walls appear to have a temperate climate, with the northern regions of the land being especially cold, rarely exceeding on the hottest summer days. However, the coldness of the northern regions of the island are alleviated by the occasional presence of hot springs.

It is evident that the central region of the Walls is at a higher elevation than the outermost territories. Some regions of the land are home to Forests of Giant Trees, where the trees are known to reach as high as, possibly due to the unique content of the soil. The lands within the Walls are also rich with various minerals and natural resources.