SHANGHAI — While much of the city’s Jewish Quarter has disappeared in the years since the end of World War II, the Ohel Moshe Synagogue is a constant reminder of how this Chinese city saved tens of thousands of Jews fleeing the Holocaust.

Built by Russian Jews in 1927 in the Hongkou district in northern Shanghai, the synagogue was the primary religious destination for the Jewish refugees who flooded into the city.

And while its facade has not changed, the building now is the Shanghai Jewish Refugees Museum. It is the first stop for many visitors seeking information about what the Holocaust scholar David Kranzler called the “Miracle of Shanghai.”...