General nouns

We only use the with general plural nouns when we are referring to a specific set within a general class of people or things.

Compare

Books are so important in my life.	I mean all books in general.
The books were all over the floor.	I mean specific books (that you and I know).

We can make general nouns specific by using an article and adding more information after the noun.

Life is wonderful. (life in general)	The life of a soldier is full of danger.(specifically the life of soldiers, not life in general) She had a life of hard work. (one specific life)
History sometimes repeats itself. (history in general)	He wrote a book on the history of boxing.(specifically the history of boxing) The country has a history of going to war.(one specific history of one country)

Inventions, musical instruments and cultural institutions

When we talk in general about inventions, musical instruments or cultural institutions (such as the cinema, the theatre, the circus, the opera, the ballet), we often use the:

The computer must be the greatest invention ever. (The computer as an invention in general, not a specific computer)

The violin sounds different to the viola.

I love a night at the opera.