The Sneeze

When Almighty Allah created the body of Adam (a.s) and placed it on the Arsh, the angels used to be amazed and afraid of it, because they had never seen something like it. 

Then He placed the soul in Adam (a.s)'s body. 

When the soul reached his Nostrils, he SNEEZED.

When it reached his mouth he said "Alhamdulillah"

Then the Almighty said "Yarhamakullah"

In Arabic, Alhamdulillah means "May Allah bless you"

Yarhamakullah means "May Allah have Mercy upon you"

So it is the Sunnah of Adam (a.s) to say Alhamdulillah when you sneeze, and its the Sunnah of Allah to say yarhamakullah when you hear someone sneeze

I bet you didnt knew that before.....