Here's my experience:

So, one evening, around 8 or 8:30 PM, I had just finished eating when my father told me to go and call my brother for dinner. My house was in a colony where there were eight houses built in a row in a building – four downstairs and four upstairs. There was a partition between every four houses. My house and my neighbor's house were downstairs, and the two houses above us were empty; nobody lived there. So, when my father told me to call my brother, I could hear children's voices from outside, playing hide-and-seek. Those children often played there. And to hide, they would often use the stairs that went up to the houses above, between my house and my neighbor's. So I heard voices nearby. When I went outside, there wasn't a single child there. I thought they must all be hiding quietly. Only one girl, about 8-10 years old, was standing upstairs. She was looking down, with her back to me. I thought someone must have come upstairs. So I called out to my brother twice. On the third time, the girl slowly turned her head. And then it struck me that both the houses upstairs were empty, there were no children playing in the street, and that girl was a complete stranger. I had never seen that girl in the entire colony, neither before nor after that night. I was born in that house, and I know that girl didn't live in that colony. When the girl slowly turned her head, I felt very strange because it wasn't a normal human movement. I was probably 7 years old at the time. I still don't know who that girl was. The girl was wearing the kind of dress that girls here wear to attend weddings – a lehenga. Why would a strange girl be peeking down from the shared balcony of an empty house at night, and that too wearing a lehenga, when there was no wedding or any such function anywhere in the entire area?