There are 2 kinds of cities right now. It explains why you hate your downtown.

The best kind of tourist attractions

There’s no one-size-fits-all strategy for boosting tourism in American cities. There’s no universal balance between visitors, residents, and workers and no single strategy to maximize economic development and social good, said Tracy Hadden Loh, a fellow at the Brookings Institution who studies downtowns and urban real estate.

But amenities with many uses and offerings satisfying a diverse array of people tend to work best. The nonprofit Project for Public Spaces describes this phenomenon as the Power of 10+ — which holds that places thrive when people have 10 or more reasons to be there.

On the flip side, amenities like convention centers and big stadiums, which tend to be car-centric and infrequently used, aren’t the best uses of space. “The more multi-purpose your facilities could be, the better off you are,” Karen Chapple, director of the School of Cities at the University of Toronto, told Business Insider.

Among the most attractive amenities are waterfront parks and public markets. Waterfronts are “unparalleled in their ability to be all things to all people,” Loh said. Parks along urban rivers, lakes, canals, and ocean beaches can attract new residents, visitors, and commercial development while serving as a buffer for flooding.

And markets are “a really special kind of infrastructure that can serve both people who go downtown every day and people who are there for the first time from really far away,” she said.

“You can program them in bite-sized pieces — a public market isn’t just one vendor,” Loh said. “And similarly, a waterfront isn’t just one activity. It’s actually dozens or hundreds of activities that can all take place at the same time in the same setting.”

Chapple pointed to San Diego’s downtown as a strong example of a diversified place with an attractive waterfront. “It has a really quite an extraordinary balance of tourist facilities, local universities, medical complexes, residents living downtown, a baseball team downtown, a waterfront — it sort of does everything right,” she said. The balmy weather year-round is also a huge perk — there’s no time of year when San Diego’s outdoor spaces aren’t usable.