Why has sleep been called a wonder?

Sleep has been called a wonder for the following reasons:

(i) It overpowers anyone and everyone.

(ii) Nobody knows exactly, what brings about sleep.

(iii) It is a common experience but nobody knows its secrets and depths.

(iv) It has the ability to take away all our fatigue and reenergize us for the new challenges.

(v) It makes us forgetful of even our dearest persons and objects for the time being.