United States National Radio Quiet Zone

Its dish is 100 metres across, the largest fully steerable radio telescope in the world.

It sits in a valley in the Allegheny Mountains, in the middle of the National Radio Quiet Zone, a 13,000 square mile area where radio transmissions are restricted by federal regulation to protect the observatory from interference.

Within the quiet zone, cell phones are discouraged, Wi-Fi is limited, diesel vehicles are preferred over gasoline vehicles because diesel engines produce less radio interference.

The residents of the surrounding communities have adapted to a life with fewer wireless devices, a life that is, in a small way, quieter than the rest of the modern world.