This expression means that "the appearance or state of someone/something in question resembles N". N is usually something which most people can relate to.
The use of まるで emphasizes the resemblance. ～よう functions as a na-adjective.
このパンはまるで石のように固いです。
This bread is hard like a rock.
このパンはまるで石のようです。
This bread is practically like a rock.
これはまるで石のようなパンです。
This is a bread which is practically like a rock.
Lesson 20-8「わたしは京都のような古い町に住んでみたいです。」
I want to live in an old city like Kyoto.