This ghetto (founded in 1516) was, in fact, the very first official ghetto existing in Europe. Even the word "ghetto" itself supposedly originated here.
There is Jewish Museum and several active synagogues located in this area. Many cultural events are often organized there so if you wish to get to know the Jewish culture better, this is definitely the best place to visit.
One of Shakespeare's most famous comedies - The Merchant of Venice - takes place here.