Overall, the festival, which has been in the works for three years, cost roughly $3.5 million to produce. But University of Baltimore economist Richard Clinch estimates that it could bring in as much as $30 million for the city this week — not a bad return on investment. Whether it does and who that benefits remains to be seen, along with whether it lasts. The organizers like to compare Light City to Austin's SXSW (South by Southwest) festival, which drew about 700 people when it began in Texas in 1987 and last year attracted 90,000 and $317 million. And light festivals are catching on, they say; they have them in Sydney and London and Montreal and Berlin.