The Little Synagogue

The Alte Synagoge in Erfurt, Germany, is one of the best preserved medieval synagogues in Europe, its oldest parts dating back to the late 11th century. Most parts of the building date from around 1250–1320. Due to the fact that its roof is still standing, it is thought to be the oldest synagogue building intact in Europe and the world.Since 2009 it has been used as a museum of local Jewish history.

Source: Wikipedia