There have been a number of articles spotted on this topic recently. In 'Travelling to the dark side', the author talks about dark tourism in general; Philip Stone's 'A dark tourism spectrum: towards a typology of death and macabre related tourist sites, attractions and exhibitions' is available online or in Ebscohost (Athens) in fulltext. Another which may be of interest is based around the Ustica Disaster in 1980; Terezin in the Czech Republic comes under the spotlight in this article which lists the top 10 darkest attractions in the region.
There is a page of links to places which have a connection to historical figures; another article discusses the experience of visiting old houses and stonewalls. The website Post-Conflict Heritage looks at the restoration and politics at cultural sites such as Angkor.