From the Fun Historical Riddles department: Where was the Declaration of Independence signed?

I keep the sunlight at my door, but welcome echoes in. Though many fear my darkest parts, great wonders lie within.

No chewing needed, just a sip, For strong bones on every trip, White mustache when you drink, What am I? Take a think!

There's a tiny round chap, keeps your coat snug in a little snap. With a gentle push or a pulling tug, it joins the fabric like a warm hug.

I stretch ahead, but never travel. I can be walked, crossed, or ruled. Some fear the end of me; others dream of it. And when cerulean becomes more than just blue, you’ve entered Miranda’s world. What am I?