The Fence Riddle

What has cities, but no houses; forests, but no trees; and water, but no fish?

I’m not a bird, but I can fly. I’m not a river, but I flow. I’m not alive, but I grow. What am I?

In a house there are 3 light switches, all in the off position. Each controls one of 3 light bulbs in a room upstairs. You can flip the switches as many times as you want, but you can only go upstairs once to check the bulbs. How do you determine which switch controls which bulb?