As preservation milestones go, 2016 offers a trifecta. Alongside both the 50th anniversary of the National Historic Preservation Act and the centenary of the National Park Service, this year also marks what would have been the 100th birthday of Jane Jacobs, the celebrated and groundbreaking urban activist who helped propel preservation into the modern era.

In her most famous book, 1961’s The Death and Life of Great American Cities, Jacobs helped articulate and promote the many benefits older places bring to cities—benefits like character, variety, affordability, and innovation. “Cities need old buildings so badly,” she wrote, “it is probably impossible for vigorous streets and districts to grow without them.” At a time when neighborhoods were increasingly being reshaped to accommodate cars, she reminded us that cities are made by, and for, people, and require lively streets and lots of foot traffic to thrive.

Today, in the wake of a nationwide urban renaissance, the truth of Jacobs’ insights can be seen all over America. In Denver and Philadelphia, Baltimore and Louisville, Birmingham and Detroit, neighborhoods are experiencing renewed vitality through the adaptive reuse of their older fabric. Historic buildings are finding new life as affordable housing, breweries, restaurants, New Economy office complexes, and community centers.

In short, older buildings attract businesses, jobs, residents, and tourists. They help us address problems like affordability, displacement, and climate change. They connect us to each other, to our past, and to our future. As we take the opportunity of these 2016 milestones to renew our movement for this century, the National Trust is embarking on an initiative to help cities all over the country benefit even more from the power and potential of preservation.

Building on our 2014 Older, Smaller, Better report, which analyzed the entire urban fabric of Seattle, San Francisco, and Washington, D.C., to empirically assess Jane Jacobs’ arguments, the National Trust’s Preservation Green Lab will debut an urban atlas project this November that applies the same methodology to 50 more cities across America. In partnership with the Urban Land Institute and others, we are also conducting in-depth policy analyses in specific cities to help them better leverage their existing buildings for growth.

My new book on this subject, The Past and Future City: How Historic Preservation Is Reviving America’s Communities, also offers a primer on the many ways preservation can enhance and enrich our cities. Because Jane Jacobs was right: Older buildings are not just aesthetically pleasing. They are remarkable social and economic engines. And, with smart preservation policies at work, they can help us attain a more vibrant future.