destroying his yacht off the coast of ireland. >> the fact a high level royal was killed by a terrorist organization really upped the game for the ira, showed they are a lethal, potent force. the fact that the ira in subsequent years tried to kill queen elizabeth shows they're a force to be reckoned with. >> they have never been more visible than they are now. according to the business valuation firm, the royal family generates over $2 million for the uk economy every year. analysts say this spring's royal wedding will only add to that. >> we're already seeing strong growth, so 15%, you know, over the last year and we would like to use this occasion to cement that growth. our american staff tell us they can see that confidence in the market. >> so for terrorists, especially a decimated group like isis,