・・・、。
Heh heh... there's a story behind that place.
Literal
Heh-heh... backstory [subj-が] exist [explain-のさ], over-there [in-topic-には].
A displaced topic at the end is a casual/dramatic pattern: the focus (いわくがある) comes first, then the locator あそこには is tacked on as an afterthought — contrast the textbook order あそこにはいわくがある. いわく (曰く) literally 'a saying / inscription' is used idiomatically for 'a backstory / reason / something behind it,' often with a sinister ring. のさ is a masculine explanatory ending combining the nominalizer の with the assertive さ.