Overtown is a ghetto located just north of downtown Miami. In the 50's and 60's it was a striving neighborhood referred to as the Harlem of the south, but when construction of an elaborate expressway system was built in the 70's cutting through the heart of the neighborhood it caused a major change. The population went from 40 thousand to under 10 thousand. The crime and murder rate sky rocketed (much do to the introduction of crack cocaine). Overtown has one of the highest murder rates in the country.
It is advised that if you don't live there or have any business there to not enter this area as it is highly probable you will be a victim of a robbery or worse. In 1993 Miami made headlines when several tourist were robbed and murdered, because they got lost in downtown which is connected to Overtown and turned into the wrong street. Take more than regular caution for a bad part of a big city.