There were thousands of "dead" spaces like the lot I had observed, thousands of transitional environments that no one saw, that had been rendered invisible because they were not "of use." Anything could inhabit them for a time without anyone noticing. We had come to think of the border as this monolithic invisible wall, but if members of the eleventh expedition had been able to return without our noticing, couldn't other things have already gotten through?

• environment
• habit
• other
• borders
• boundaries