Cities are constantly changing What often remains are the cellars as parts of buildings that exist underground which are less exposed to the pressures of modernisation and destruction events In many places this historical layer of cellars carries information about the history of urban development that has been lost above ground Which methods can be used to make this source accessible and which research questions can be answered with the information obtained from it Renowned researchers discuss current results and approaches to these questions Particular attention is paid to aspects of urban research and the question of the extent to which the transformation of cellars reflects urban development processes