During season 3 a few days after seeing the ocean for the first time one night has they where sleeping back at HQ survey corps headquarters they both in their sleep saw a symbol out of nowhere and then woke up in a forest like area. There was two paths one path was really big going out to more trees and land. The other path was smaller leading to like the first path. The second small path had a medal swing structure that holds four swings.

Armin: huh?….. where I’m I?……