
Casterly Rock
is an impregnable FORTRESS.
Game of Thrones Season 7, Episode 3

The greatest FORTRESS ever built.
Game of Thrones Season 2, Episode 7

I'd call it a
"Fortress of Solitude for babies."
The Big Bang Theory Season 10, Episode 6

and abandon this FORTRESS
you can no longer hold.
Game of Thrones Season 4, Episode 8

Welcome to my FORTRESS of solitude.
The Big Bang Theory Season 8, Episode 7