The movie Romeo and Juliet 1968 was very authentic in the sense of places that the scenes took place. One of the reasons for this was that they filmed most of the scenes in Italy. And, when you combine the elaborate Rennaiscnce costumes, direction of Franco Feffirelli, the beauty of Italy, and the elequent words of Shakespeare, you get a timeless classic.
The Making of Romeo and Juliet
from Franco Zeffirelli's Autobiography
Three Magical, Unforgettable Months
The making of Romeo and Juliet
from Michael York's (Tybalt) Autobiography
At the bottom of this page are links to "The Making of R&J" from Franco Zeffirelli's autobiograpgy, and "Three Magical Unforgettable Months" from Michael York's autobiography.
    The first fight scene was flimed near Fontana dei Matti in Guggio.  This courtyard was swept with the bright oranges and yellows of the quarllesome Capulets and the deep blues and maroons of the Montagues as clanging swords sliced through the air.  The main square of Verona, however, where the prologue, death of Mercutio and death of Tybalt took place was reconstructed on the backlot of Cinecitta Studios in Rome.
    The conversation with Romeo and the nurse and the Friar's cell were shot in the ancient Bascilica of St. Peter in Tuccania.  This is where the amorous lovers Romeo and Juliet got married.  Also, believe it or not, the death scene in the crypt was also filmed in that same church, although in a different area.  The columns have always been there., and all Zeffirelli had to do was add a few granite slabs and, Voila! The perfect place for the saddening tale of this to come to its tragic conclusion.
    Also in Gubbio, is a narrow and steep street called Via Ducale.  This was where the dreamy-eyed Romeo walked by with his little flower, leaned up against a wall and went to sit on a nearby wall bench.  The house at which this is located and its gothic style entrance was where the injured Montagues were taken.  Nearby there is a short brick parapet where Benvolio sat and tried to comfort Romeo.
    Palazzo Piccolomini in Pienza waas where various locations in the Capulet mansion were shot.  From the main courtyard, where we see Juliet hearing the call "Rooomeooo," to the upstairs where they filmed such scenes as Juliet rushing to meet her mother, Lady Capulet's bedroom, and the conversation between Capulet and Paris.
     I believe that the reason for the movie's amazing influence on viewers is its authenticity that really takes you back to the 15th Century Verona.  This lets us experience the tragic story with the lovesick heroes.