Ark of the Covenant

As mentioned previously, the Ark of the Covenant was the most holy object of ancient Judaism, holding a central place in the Tabernacle and Temple and even being associated with the fortunes of the whole nation. LEGO has a very small replica in one of the Indiana Jones sets, but AFOLs (Adult Fans of LEGO - hobbyists who collect and build with LEGO) have designed much better versions, such as this by Matija Puzar (there's also an earlier version if you follow that link).