Why Aeroplane windows are round?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

What does this rebus picture identify?

What is the riddle which can be asked all day with a different correct answer each time.

If I put in one bird per cage, I have one bird too many. If I put in two bird per cage, I have one cage too many. How many cages and birds do I have?

There is a certain crime, that if it is attempted, is punishable, but if it is committed, is not punishable. What is the crime?

Chocolate costs 6 rupees and a Toy costs 5 rupees. If you have 32 rupees in total, how many chocolates and how many Toys can be purchased with that amount?

Spot 5 differences in two Christmas tree below:

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.