Atlas Obscura, a “compendium of the world’s wonders,” has a nice write-up of Downtown Tulsa’s most famous landmark, the Center of the Universe:
The center of the universe is an acoustic anomaly; when one stands in the center of the circle and makes a noise, that noise is echoed back several times louder than it was made. Imagine dropping a small pin and expecting to hear a tiny “tink” as it hits the floor. Instead, the sound the pin makes is more like the loud crash of a gong.