I remember, years ago when Attack on Titan started airing again with season 2 and the guys were talking about it on the Friendcast, they were talking about how casually it dropped

Guys I just finished the first season of this anime Attack on Titan I can't wait for season 2!!! : r/okbuddyreiner

Explaining the Confusing Time Jumps In Attack On Titan Season 2

3.) What did Eren mean when he said Ymir was waiting for him for 2000 years, and that he saw all the memories or something? - Quora

Explaining the Confusing Time Jumps In Attack On Titan Season 2

Historia (Episode), Attack on Titan Wiki

Attack on Titan Season 4 Episode 12 Review: Guides

Calaméo - Sitchin - The 12th Planet

Attack on Titan/Shingeki no Kyojin Rewatch - Season 2, Episode 9 Discussion : r/anime

Explaining the Confusing Time Jumps In Attack On Titan Season 2

To You, in 2000 Years: The Fall of Shiganshina, Part 1, Attack on Titan Wiki