[Chance Hart]

You are probably thinking of Montezuma's Castle. I remember the day when you could climb up and into it without a guide. Used to find all kinds of little Treasures. :-)

[Louis Foxwell]

Visited Hovenweep years ago before it became controlled. A fabulous ancient ruins.

[no-s]

You are probably thinking of Montezuma's Castle

Ah, yes, that's right. For those structures made of mud to have survived for so long they need to have remarkably similar siting, and other properties. "Other properties", haha, yeah they need to be next to river valleys for conveniently growing crops nearby. Hence the canyon wall siting.

Actually when I visited Montezuma's Castle 30+ years ago the guide only warned us against entering the upper structure, but we did accidentally wander into into the off-limits area as we were chatting with some cute archeologists.