This is where the foals discover the Isle of Berk in The Alliance of Berk and Equestria.
[The foals follow the passage way]
Snowdrop: Where does it go?
Skyla: I don't know.
[Then, when they reach the other end they take a look at the town.]
Yuna: Wow, it is a town!
Nyx: Look at it, just look at it!
Skyla: Hey, look what lived this town!
[they notice the town is inhabited by Vikings]
Yuna: They're Vikings! Real vikings!
Nyx: Amazing!
[then a dragon flies by]
Skyla: Whoa! There's dragons too!
Snowdrop: Their town must be under attack!
Yuna: Wait a minute, those dragons aren't fighting them. They're, interacting with them!
Nyx: Why?
Yuna: I'm not sure.
Skyla: Maybe they're like Spike.
Nyx: You never know.