Dunno where that picture is from, it makes it look much more like a human construction, here's a more recent pic. If you want to learn more about this rock wall, here's a link.

TL;DR It's sandstone that fractured (something sandstone does all the time) but happened to fracture into a pattern that looks like stacked stones. This apparently happens a lot to rock that is underground and while there were legends of arches and hallways and even "metal tools" there is no actual evidence to say those existed and the "metal tools" where simply iron deposit in the earth which happens all the time.

2 square miles in length

From the man with 2 inches of brain mass and 13 oz of IQ.

Just in case anyone wanted to actually learn something from this...

PS is short for postscript. If you have a postscript after your postscript, it's a post-postscript, or PPS, not PSS.

How fucking dire is the state of online disinformation that one of my main thoughts was "Well at least they're calling the park by its actual name instead of trying to make it part of a stupid culture war."

I don't remember where I heard it, but if your evidence starts and ends with "It looks like..." then its probably bullshit.

I’d listen to Beaker from The Muppets before you, bro.

Post script script

Basically completely debunked by magnetism - https://youtu.be/ivRHHqtBhAI