3-4 hours: Detailed walking tour through the Jewish museum
The former Jewish quarter borders with the Old Town.There were Jewish settlements since the 12th century. Later the Jews lived there separated and isolated in a ghetto. The thousand years long history of the Prague's Jews is well-kept in the synagogues. The Old-New synagogue is the oldest active synagogue in entire Europe. Several other synagogues, the Old Jewish cemetery and the nearby Ceremonial hall are nowadays part of the Jewish Museum Prague.
(Jewish Museum: 500 CZK / 370 CZK - 50% discount with Lítačka)
Maisel synagogue - Spanish synagogue - Pinkas synagogue - Old Jewish cemetery - Ceremonial hall - Klausen synagogue - Old-New synagogue
If you'd like to visit more Jewish sites in Prague, it's possible to do a full day tour (Jewish Quarter and Jewish Prague after 1945).