Dead Sun - The bridge at the border of the Dawn-region

Somewhere between the Dawn and Midnight-region, there is a huge gap dividing the land. The only way to cross it is a bridge that automatically pushing itself out and pulling back in, operated from a building next to it. However, the human-made building is also long abandoned, and the bridge is rolled back. The advenas who patrols this border area making an advantage of this gap, preventing humans from crossing more effectively.