Larson said the DDP is investing at least $100,000 in park activations alone. The hope is to provide a favorable first impression for not just the kids participating in the competition, but also parents, teachers, spectators and company representatives who eventually might invest in the city themselves.

The FIRST Championship will take place at Cobo Center, with opening and closing ceremonies at Ford Field. Organizers have signed a three-year deal to host the event in Detroit at a time when the state is aggressively advocating STEM education.

"We looked for a host city that makes sense for the whole story," Mark Giordono, vice president of development for FIRST, told Crain's last week. "We're showing the city off as a place you'd want to work, live and play."

The Detroit visitors bureau booked the event for the city in 2015 and has studied previous events in St. Louis and Houston to prepare, said Renee Monforton, communications director for the bureau.

DMCVB Executive Vice President Michael O'Callaghan added: "We worked for years with FIRST to convince them to come to Detroit."

He declined to say how much money the bureau invested for hosting preparations.

DMCVB is helping arrange transportation from Detroit Metropolitan Airport to the city, and it will staff 100 volunteers at the airport and downtown to welcome visitors. It is also putting up digital welcome signs at the airport, as well as signs at 50 regional hotels and around the downtown area. It organized a restaurant and retail program in which FIRST visitors receive discounts at more than 40 downtown establishments. It also worked with metro Detroit hotels to block out 25,000-30,000 hotel rooms to accommodate visitors.

Besides the long-term benefit of crafting a positive image, organizers say the city will also see a $30 million economic impact. Larson said the direct spending will take place mostly in the immediate downtown area where the event takes place — on lodging, food, beverages and shopping.

When it comes to hosting large-scale events, "We start with city resources and assets, working through security plans and traffic management to overall delivery of city services," Larson said. "Then we start really thinking about: What are things the visitor is going to enjoy?"