The Altstadt is a city district of Frankfurt am Main, Germany. It is part of the Ortsbezirk Innenstadt I.
The Altstadt is located on the northern Main river bank. It is completely surrounded by the Innenstadt district, Frankfurt's present-day city centre. On the opposite side of the Main is the district of Sachsenhausen.
As the historical center of Frankfurt, the Altstadt has existed from Frankfurt's beginnings, dating back to 794. It used to be part of the original Innenstadt area, which lay inside of the city walls, the Staufenmauer. Only very small sections of the Altstadt were rebuilt after World War II and so only a few old buildings are actually preserved.
Wikipedia https://en.wikipedia.org/wiki/Altstadt_(Frankfurt_am_Main)
More information on Frankfurt's official website http://www.frankfurt.de/sixcms/detail.php?id=2835&_ffmpar%5B_id_inhalt%5D=12690
Address 19 Saalgasse, Frankfurt am Main 60311, Germany
Coordinates 50°6'34.776" N 8°40'56.467" E