Introduction to Princes Street in Edinburgh: Princes Street is the busiest street in Edinburgh. It is located on a long hill between the old and new cities of Edinburgh. It has clear natural barriers. The total length of the street is only one mile, with shops on both sides. Lined with streets, the north of the street is the new town that rose up after the 18th century, while the old town on the south of the street maintains a distinct medieval style. At the east end of the street is the picturesque Princes Street Garden, known as "the most beautiful road in the world" known as.