If the source is ‘The Forward’ they are reliable. If the source is ‘Myths and legends’ they are not only unreliable but anyone who goes in search of such treasures deserves to be turned into a frog by an evil sorceress. In any case, since you are asking for my expert opinion, I will tell you that it’s unlikely that there are still undiscovered treasures. Too many holes have been dug for a treasure to be overlooked -if by treasure we mean something worth more than twenty dollars (personally, I refuse to exhaust myself digging a hole for less than twenty dollars, and that’s my last word on the subject). As for the giants, I think six heads are too many heads. Five-headed giants might exist, but certainly not in Brooklyn. I once met a drunkard in a harbor side tavern who assured me he had run into a multiple-headed giant in Istanbul. However, the giant was not guarding a treasure but a faulty shipment of vodka destined for destruction due to its excessive alcohol content. According to my informant, he personally helped the giant to get rid of the vodka and to change the empty bottles for ten cents each.