Who's watching you today.

A huge number of webcams are unsecured, meaning that anyone on the internet can access the feeds. As they have web front ends, Google even lists them in their search indexes, making them even easier to find. Eg: Google search.

Some websites are even dedicated to listing unsecured cameras.
Here's some examples:
livesecuritycams.com

Most of them a pretty mundane, car parks and the like.

There's also lots of deliberate sharing, like this guy with a camera on his truck:
bigrigtravels.com