Difficult

I am round as a bowl, deep as a tub, but all the world's water couldn't fill me up.

There is a puzzle which can be asked all day with a different correct answer each time. What is the puzzle?

A man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

What types of words are these: madam, civic, eye, level?

Riddles and Answers