Example of an extension where Normal of a Normal extension is Normal.

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We know that in general Normal extension of a Normal extension may not be normal. I want an example where it holds, i.e Normal extension of a Normal extension is still Normal. Is there any example of such extension ?

Thank you.

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Here is a non-trivial example: For $\mathbb Q\subset \mathbb Q(\sqrt 2)\subset \mathbb Q(\sqrt 2,\sqrt 3)$ all the three extensions

  1. $\mathbb Q\subset \mathbb Q(\sqrt 2)$

  2. $\mathbb Q\subset \mathbb Q(\sqrt 2,\sqrt 3)$

  3. $ \mathbb Q(\sqrt 2)\subset \mathbb Q(\sqrt 2,\sqrt 3)$

    are Galois (and thus normal) extensions