Mountain lions aren't real common here in Los Angeles, but they do exist.
I saw my first one this afternoon, about two good Frisbee throws from our house.
We get a lot of wildlife in our neighborhood, since we're literally on the very edge of town, but mountain lions are not seen often. To the north of our house is the Angeles National Forest. Here's a rough idea where we are in relation to the rest of the LA area.
And zoomed a little farther back, to show where the other 8 million folks live:
Anyway, that was my urban wildlife adventure for the day.