Text by Rabbi Berach SteinfeldThe Torah in Devarim 13:17 tells us that in the event there is a whole city that serves Avoda Zora [idol worship], all its belongings will be gathered in the middle of the city and get totally burned. The Gemara in Sanhedrin 71a tells us that Reb Eliezer says that if a city that served avoda zora has even just one house with a mezuzah in it, the city will be saved.