When I was 11 years old
I had a friend who had an electric train set in his attic. It was above the bathroom in the house. He had two sisters;one my age and the other was 15. There was a hole in the roof and whenever his sisters would shower or use the toilet we would be able to see them. There was a rug over the hole.
One day his sisters had a swimming party and I saw at least five naked girls. Some were around 16 or a little younger.
I really enjoyed doing this when I was a kid but as I got older it began to bother me that I had spied on innocent girls like this. Along came the internet and there is no reason to do anything like this anymore. The boys family sold the house and they moved away.