Thanks to the Robert Wood Johnson Foundation for underwriting this special two-part series

about the power of sound to affect and influence our health and well-being.

The Robert Wood Johnson Foundation is working alongside others to build a culture of health

for everyone in America.

Learn more about them at rwjf.org.

This is 99% Invisible.

I'm Roman Mars.

Nearly everywhere we go, we're bombarded with human-made sound.

It's especially bad in cities.

Cities in the past think about where you'd have horses and buggies.

You hear clopping, you'd hear banging of wood against stone.

Very noisy experiences.

That's Joel Beckerman.

He's a composer and founder of a sonic branding and design company called Manmade Music.

Then cars came along and we're sharing the road with these horses.

And so not only did you have the horses at one rate of speed, the cars at a different

rate of speed, so lots of honking of the horns, it must have been a cacophonous mess.

But things got even worse when cars came to dominate the roads.

If you fast forward to really what the soundscapes were, let's say in the 50s.

So in the 50s, it was all about muscle cars.

It was all about the loudest car you could have, Mustangs, Corvettes that were really,

really loud.

...