A cardo is a wide main street in the heart of a settlement or city. This Cardo in Jerusalem was built by Romans starting in 135 AD. It started at the Damascus Gate and heads south to the city center. When it was finished, it extended from the Damascus Gate to the Zion Gate (which was east of the present Zion Gate). The Cardo was 75 feet wide. and had a central road for pedestrian and wagon traffic and two avenues of columns - one on each side. There were typically shops on each side, but in Jerusalem there were shops only on the eastern side in certain parts of the Jewish quarter.
Today the columns and street can be seen and there are modern shops on either side.