Aaronson House. During the First World War, Zichron Yaakov was used a center for underground activity by NILI, the first Hebrew secret organization. Siblings Aaron and Sarah Aaronson were its leaders, and their family home, the location of the organization’s headquarters, is now a museum where you can learn about the underground members’ activities, how they were caught and their ultimate fates. Beside the family home is Aaron’s house, where by all accounts Sarah killed herself after being apprehended.