Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?
What is the Surname of Barbie Doll?
There was an aeroplane crash, every single person died, but two people survived. How is this possible?
When it is alive we sing, when it is dead we clap our hands. What is it?
Forwards I am heavy, backward I am not. What am I?
I don't get anymore wetter, no matter how much rain falls on me.
Why do people go to bed?
What does Alexander the Great and Winnie the Pooh have in common?
Who can jump higher than a Mountain?
I shave every day, but my beard stays the same. What am I?
The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total. How much time will he take to have all the five tablets?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.