The definite article ‘the’ designates a specific person, place or event as shown below:

Specific things.The book I bought is interesting.
Pass me the sugar please.
The milk is in the refrigerator.
Hotels, monuments, buildings, museums, cinemas, theatres.The Ritz, The Tower of London,
The Empire State building, The Louvre,
The Odeon Cinema, The Royal Theatre
Mountain ranges, rivers, seas, oceans.The Alps, The Mississippi,
The Black Sea, The Pacific Ocean.
Groups of states or islandsThe United States of America,
The Bahamas.
No article is used in the following cases :
GeneralisationsSugar is sweet.
Caviar is expensive.
Streets, squares, etc.Oxford Street, Time Square
Names of mountains and lakesMount Everest, Lake Ontario
Countries (except groups as above)England, France, Japan, India, etc.
ContinentsEurope, Africa, Asia, America, Australia