Learn French: L'Europe est une région magnifique. - Europe is a magnificent region.

French requires definite articles (le, la, l', les) before the names of continents, countries, and large regions. Because Europe begins with a vowel, it takes l'. You will usually only drop this article after certain prepositions, such as when saying en Europe (in Europe).

Since région is feminine, why doesn't the adjective magnifique change to match it?

When a French adjective already ends in an unaccented -e in its default masculine form, it does not take an extra -e for the feminine. It remains exactly the same for both masculine and feminine nouns.

Could I say une magnifique région instead, placing the adjective before the noun?

Yes, you can. While magnifique typically follows the noun for a standard, objective description, moving it before the noun (une magnifique région) adds a subjective, emotional, or poetic emphasis to just how beautiful you find it. This is a common stylistic choice in written French.