It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

What kind of storm is always in a rush?

Can you replace the question mark with the correct number in the below table sequence?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

I am the fastest animal but cannot climb the tree. What am I?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?