I'd rather ask here instead of making a new thread. Most of the discussion has been about soil and sand. How about souvenir water from places like the Trevi Fountain or holy water from the Vatican? I'm more concerned about the local laws/customs in such places, not US border control, as I have brought river/lake water and beach sand back to the US before with no problems (might also pop this in the Italy section). I don't want to offend religious/spiritual requests or debate over superstitions (like Hawaiian lava rocks). It would be no more than a few 30ml vials and easily fit in my 1-quart bag.