Learn Italian: La fontana in piazza è molto famosa. - The fountain in the square is very famous.

Molto famosa simply means 'very famous'. If you wanted to use the relative superlative to say 'the most famous fountain', you would use the definite article and più, making it la fontana più famosa.

Is there another way to say molto famosa in Italian?

Yes! You can drop the word molto (very) and add the suffix -issima to the end of the adjective. So, molto famosa becomes famosissima.

Why is it just in piazza instead of nella piazza (in the square)?

For many common city locations and rooms in a house, Italians use the simple preposition in without combining it with a definite article like 'the'. Just like we say 'in town' or 'in school' in English, Italians say in piazza (in the square), in banca (in the bank), or in centro (downtown).

Why does famosa end in -a here?

Adjectives in Italian change their endings to match the word they describe. Since la fontana (the fountain) is a feminine, singular noun, the base adjective famoso changes to famosa to match it perfectly.