Did any of your ancestors stay in Antwerp, Belgium in the 1840-1930 timeframe? Then you may find information in the Antwerp Police Immigration Index, searchable at Familysearch.
This leads you (hopefully) to an index record formatted like this, with a "File Number". Now you can get details on that file through this page on the Dutch website ZoekAkten, by locating and browsing the film contaning that File Number.
These files can contain very valuable information like origin, dates, relationships, photo's, etc.