One of Sydney's best museums revolves around a detailed and expertly curated exhibition on the Holocaust, with sobering personal testimonies and moving objects as well as a memorial section for the 1.5 million child victims. Other sections cover the history and practice of Judaism itself and Australian Jewish history, culture and tradition. A section on the top floor examines contemporary human rights challenges, while temporary exhibitions are always excellent. There's also a kosher cafe.
Sydney has had an important Jewish history from the time of the First Fleet (which included 16 known Jews), to the immediate aftermath of WWII (when Australia became home to the greatest number of Holocaust survivors per capita, after Israel), to the present day.
Visiting on a Sunday or weekday afternoon is recommended, as the museum often packs out with school groups.