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?

There is a place where if I stand up straight, I will still be considered sideways.

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.
How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

The below mentioned letters have been placed in a order using a logic.

DEAD, BALL, FEAR, SHOP

Can you find the logic?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

Can you place six X (crosses) in below board without making three in a row in any way ?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

What is so fragile that saying its name breaks it?