What is answer of 'In a marble hall white as milk'?

What is the answer of question In a marble hall white as milk from Riddle Me? Internet media is the best way to find out such answer i mean answers of very difficult questions which includes riddles. And lately, many are searching the solution Riddle Me: “In a marble hall white as milk…” is given below.

In a marble hall white as milk, lined with skin as soft as silk. Within a fountain crystal-clear, a golden apple doth appear. No doors there are to this stronghold, yet thieves break in to steal its gold.

And the answer to this riddle… an egg.