Optical illusions tend to get the lion's share when we talk about things that make us question reality, but acoustic anomalies can be equally trippy especially if they were not designed with the intention to confuse and mystify. This is the case for the "Center of the Universe", a peculiar phenomenon known as a sound anomaly.

The "Center of the Universe" is in Tulsa, Oklahoma

Located on a pedestrianized bridge in Tulsa, Oklahoma, it is marked by a spot on the floor with a concrete circle and surrounded by planters and benches that form a wider circle around it. The spot itself is only around 76 centimeters (30 inches), with the wider circle around 2.5 meters (8 feet) across. Curiously, when you step into it, your voice is echoed back at you but much louder, and yet your voice is inaudible to anyone standing outside it. Only the person inside the circle hears the strange distorted echo. The voice of someone standing outside the circle is also distorted and will sound strange and unclear.

You can see and hear it in action thanks to this video that shows the echo effect from inside the circle and how people outside the circle can't hear what you hear.

What causes the sound anomaly? 

There is no official explanation for how the anomaly formed, but the most likely cause is the planters around the circle acting as parabolic reflectors, reflecting the sound waves and creating the peculiar effect. 

Are there other sound anomalies?

There are other acoustic anomalies around the world, including the Mystery Spot of Lake George, which is also created by a small round stone structure that generates an acoustic abnormality.

Such weird sound displays are also found in circular buildings. The dome of St Paul's Cathedral in London is known as a whispering gallery, where your hushed tones on one side are delivered across the huge dome to people who can hear you clearly on the other side thanks to the reverberation of sound waves.

Similar structures that create the same effect can be found in many buildings both ancient and modern, from the Maya city of Chichen Itza to Grand Central Station in New York.

An earlier version of this article was published in October 2021.