I wouldn't recommend a trip to Lodz but if for some reason you decide to come here and you want to see something striking, this cemetery is a good place. It's the largest Jewish cemetery in Europe with more than 180,000 people buried here. In some ways, it shows perfectly well the before and after of World War II and the Holocaust in Poland. The before is represented by the countless graves spread over endless acres, including a few almost palatial tombs of rich industrialists, but mostly the much more humble graves of ordinary Jews. This shows how important the Jewish population was in Lodz. The after is represented by the decrepit and overgrown condition of the cemetery, which appears to be open (and barely maintained in most sections) thanks only to the generosity of a few people. In places, it is almost like a jungle or rain forest and you cannot see the gravestones for the trees. The other way the war and Holocaust are represented here are the plaques on the wall honoring those who died in the Lodz Ghetto or the death camps. Very moving.
If you have a relative buried here and want to visit the grave for the first time, contact the cemetery before going (there is a web page) and arrange for a guide to take you around, otherwise you'll probably never find what you are looking for.