Leaders of No Boston 2024 and No Boston Olympics are showing opposition groups elsewhere how they helped turn public opinion against the city`s bid for the 2024 summer games, forcing organizers to withdraw.

Some were in contact with organizers in Toronto, which briefly considered hosting the 2024 games before deciding not to apply. And a few travelled to Germany to speak to the Olympic opposition in Hamburg just weeks before that city rejected a bid of its own.

"Our primary motivation was always Boston and what`s right for this city," said Christopher Dempsey, a co-founder of the No Boston Olympics group that spoke in Hamburg. "But if there`s an opportunity to share what happened here — which I believe was a very powerful thing — then we`re not going to turn that down."

Most say the debate opened their eyes to broader issues around the Olympics and other international sporting events that require cities pay for massive building projects that often leave them saddled with debt and venues that aren`t usable afterward.

Artur Bruckmann, a graduate student the University of Hamburg, said Boston is "proof that even a very small group of people with very little money can overcome one of the world`s biggest corporations" — the International Olympic Committee.

Bruckmann credits Boston organizers with encouraging them to re-double their efforts on social media. That push — combined with other major forces, including Europe`s Syrian refugee crisis — led to a surprising turnaround: Hamburg residents narrowly rejected the 2024 Olympics bid by a vote of 51.6 percent to 48.4 percent, despite polls suggesting over 60 percent support for the games prior to the vote.

With Hamburg out of contention, only Paris; Rome; Budapest, Hungary; and Los Angeles — the city that took Boston`s place as the U.S. Olympic Committee`s pick — are vying for the 2024 games. The IOC is expected to decide on a host city in 2017.

Toronto was a possibility for a short time, but opponents there say Boston activists shared tactics for educating the public and influencing politicians.

"We only had six weeks to respond to Toronto`s last-minute bid, so No Boston`s support helped us get up and running quickly," said Dave Wilson, who helped found NoTO2024.

Janice Forsyth, a Canadian professor who reached out to Boston opponents to learn about how they revealed crucial details through public information requests, hopes lessons learned in Boston and elsewhere can be codified so other opposition groups can quickly mobilize.

"That level of information sharing is critical," she said. "The same template could be used in Paris or wherever because the general pattern for bids is the same pretty much wherever you go."

The Boston activists said they`re simply paying forward the help they received early on in their efforts from Olympics opponents in Vancouver and London, two cities that recently hosted the games, and Chicago, which lost its bid for the 2016 Summer Games.

"We`ve become part of this network, with people mentoring each other and giving advice," said Robin Jacob, a co-founder of the No Boston 2024 group. "And it gets bigger every year."

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