The "Kahal Kolonia" dates back to the 11th century as the oldest Jewish community situated north of the Alps. Today it is located right in the center of Cologne; in the Middle Ages, this was one of the most important large cities in the world — a bustling commercial metropolis.
Archeologists are piecing together what the neighborhood was like a millennium ago. In addition to digging up structures like the synagogue, there are also smaller artefacts found here that provide an insight into Jewish life in the Middle Ages.
https://www.dw.com/en/will-cologne-soon-have-its-own-jewish-unesco-world-heritage-site/a-55540386