The so-called Center of the Universe in downtown Tulsa is marked by a small concrete circle in the middle of a larger circle of bricks. It’s not much to look at, but looking isn’t really the point.
The “Center of the Universe” is a little-known mysterious acoustic phenomenon. If you stand in the middle of the circle and make a noise, the sound is echoed back several times louder than it was made. Even more strange, no one standing outside of the circle can hear a thing. It’s your own private amplified echo chamber.
As the legend goes, a foghorn could be going off in the center of the circle and those on the outside wouldn’t hear it. This may be an exaggeration, but your voice does sound extremely distorted when heard from outside the circle. It’s an incredible effect. Still, though many people have studied the cause of the odd anomaly there’s no clear consensus. (Source)