Answer: Redmond, Washington
Some places on Earth are naturally calm because of their isolation and the absence of environmental disturbances, such as the sterile snowfields of Antarctic or the sprawling and deep limestone caves located under the state American Kentucky. As strangely silent to the human ear as these places, yet it is a busy street compared to the silence found in an artificial chamber located in Redmond, Washington.
In Building 87, on Microsoft's campus, you'll find an anechoic chamber, designed to absorb and isolate the sound, built by Eckel Industries and certified by the Guinness World Book of Records as the most popular place. The room is It is effective that the ambient noise level inside is actually -20.6 decibels and close to the total void of the sound, in accordance with the Brownian movement which records a level of -23 decibels.
So, why would Microsoft want to create such a quiet room? They use it to test the noise levels generated by their devices, such as the Surface tablet for example, and plan to use these precise acoustic measurements in their future projects.
Visitors to anechoic chambers report that it can be extremely discomforting to spend time there, as the walls effectively absorb the finest sounds of the environment (such as wrinkling clothes or coughing) . The silence confuses the brain enough that some people report dizziness, nausea and other uncomfortable reactions while standing inside the rooms.
photo by Andrew Eckel/ Wikimedia.