Six American cities are among the most innovative in the world, according to a report published Monday by 2ThinkNow, an innovation research firm. The US has the most cities considered top-tier innovators.

The report catalogs the world’s largest cities and ranks them by their ability to generate ideas. In order for a city to be innovative, 2ThinkNow found it should be culturally rich, have a large education, research and development base, as well as be networked with other markets.

Read: The Most Innovative Cities In America

In order to reflect the impact of innovation, we looked at filings from the US Patent and Trademark Office and tallied the number of patents originating in each city. Innovative cities produce among the most patents in the country.

According to the report, an innovative city must have “cultural assets,” which include “music, sports, languages and includes practical measurement of sports stadiums, art galleries, museums, walkability, and bicycle friendly neighbourhoods.” “Cultural Asset cities are ready for design-led innovation, and they are places you go to inspire and design new ideas. They are part of the idea stage of innovation.” American cities like New York and European cities like Vienna and Paris rank very high in this category.

Second, a city must have “human infrastructure,” meaning universities and businesses that specialize in research and development. This is, according to the study, because this helps with the development of ideas. Boston and San Francisco are perfect examples of cities with a high level of this kind of infrastructure. This is “largely because they balance start-ups, mid-size firms and corporations.”

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Finally, cities must have “networked markets,” meaning they are able to share those ideas with the rest of the world. This usually comes in the form of physical trade or digital communication. New York City, which receives the highest score in this category, is one of the most globally connected metropolitan regions in the world due in part its global financial exchanges. Los Angeles and Philadelphia also score high in this category.

These are the Most Innovative Cities in America.