“THINGS AIN'T WHAT THEY USED TO BE.” That song, penned in Harlem by Duke Ellington, could very well describe the nature of the Manhattan neighborhood today. Harlem, after all, is in the midst of massive change, with glass-and-steel co-ops, former U.S. presidents, and Starbucks moving into what had been, for a century, a ghettoized African-American community. Invinciblecities.com unveils what Harlem was 30 years ago, what it is now, and its many iterations along the way. Featuring the photography of Camilo José Vergara, the site begins in the tumultuous '70s and traces the history of Harlem since then through Vergara's photos, which he has taken and meticulously documented over the decades.

The photographs form part of a larger endeavor to chronicle the American ghetto. Launched in 2003 with Vergara's images of Camden, N.J., and Richmond, Calif., and updated in 2007 with Harlem, the website provides a sweeping look into these three communities. The site's name comes from a line in a Walt Whitman poem that is inscribed on Camden City Hall: “I dream'd in a dream, I saw a city invincible.”

Trained as a sociologist, Vergara started photographing conditions of poverty in 1969. He quickly recognized architecture's dynamic character and its potential to convey narratives: “I realized early on that buildings tell stories very clearly and each of them tells it differently.” He records each shot's location precisely, giving the project historical gravitas. The site's design is eminently user friendly, allowing visitors to easily arrange photographs based on date, location, architectural features, or themes.

Vergara has lived in Harlem since 1970. A former MacArthur fellow, he collaborates on the website with Howard Gillette, a historian at Rutgers University. “I've been shooting these places for a long time, on 35 mm Kodachrome,” Vergara says, “and the internet has become a great way to make the medium speak very directly.”