Arrange a surprise proposal with a street caricaturist. Have the caricaturist sketch a picture of you two with word bubbles that say, “Will you marry me?” and “Yes!” or Ask the divers at an aquarium to put on a proposal show inside their biggest fish tank. Give them a (waterproof) sign that says, “Will you marry me?” to hold up against the glass and then position yourselves for what will, at first, seem like feeding time.
