What has many keys but can’t open a single lock?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

Can you spot the hidden girl in the picture below?

what one word does the below rebus identifies?

There are forty elephants and they have forty-fore heads. How can this be possible?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

What you cannot hold but it is yours?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

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