After generations of passing down knowledge, years of gathering resources, months of planning, the higher ups from the society finally had their chance when Uriel discovered a way inside the dungeon.
They knew it existed, they knew it had to be somewhere in what used to be called the state of Texas, but those who knew its location died without being able to pass it down to their descendants.
All they had to go by where the disjointed pieces of a puzzle far greater than any of the ancient families could understand by themselves, put together only after the dungeon was opened. It didn't amount to much and couldn't even be called a book, it was just a few pages here and there about the contents of the dungeon.
Had that been all, they might have still been able to find the place by themselves if not for the pages being written in different languages ranging from an old form of english to french and even some ancient languages long forgotten.