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?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

Seek and Puzzle: Only the Sharpest Eyes Can Spot the Hidden Star in 10 Seconds

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.