More than ten years ago, John Rosenthal, president of the Boston real estate firm Meredith, conceived plans for an ambitious development in the Kenmore Square neighborhood to be called The Fenway Center. Just this month, the city’s department of transportation finally approved the five-building project. As American cities become denser, the low-lying fruit of real estate becomes scarcer, leaving developers and municipalities to cobble together more challenging sites. Such was the case here. While it redevelops two surface-level parking areas—themselves prime candidates for redevelopment—these areas happen to be bisected by the Massachusetts Turnpike. The transportation department had to sign off on a 99-year lease of the air rights over that segment of thoroughfare.

“There are a lot of reasons why no major air-right developments have been constructed since Copley Place in the 1980s,” said Rosenthal. In his estimation, much of the resistance came in a form familiar to most U.S. developers: an aversion to increasing density. “The surrounding communities had to accept more density than they would have originally liked, the city of Boston and the Boston Redevelopment Authority also had to approve more density than they too would have liked,” he said. All told, the $500 million project will include three residential buildings and a parking garage in the first phase, followed by a 27-story mixed-use tower in a second phase.

There were technical challenges, too. Two acres of the 4.5-acre site will be made to appear out of thin air. A deck, engineered over the turnpike, will transform an urban void into a new ground plane. “We first need to build the site,” explained The Architectural Team project manager Jay Szymanski. “It’s new land that doesn’t yet exist.” The first step, set to begin this fall, will be to construct a 70,000-square-foot deck, which will take 18–24-months to complete. All told, the first phase of this two-phase development will yield 420 residential units dispersed across three buildings, 50,000 square feet of ground-level retail, and nearly 1,000 parking spaces (750 of which, crucially, will be shared-use spots for the surrounding communities).

The site is wedged between several important Boston neighborhoods, each with a different character, including Fenway Park, the Back Bay, Brookline, and Longwood Medical Area. “We see it as a transformational project,” said Szymanski. “It’s an opportunity to connect these different neighborhoods, so we designed the massing and open spaces as a gateway between neighborhoods.”

“There’s a tremendous opportunity—and responsibility—to provide the best pedestrian experience in the public realm, and to create new connections between existing neighborhoods,” said Rosenthal. To do this, The Architectural Team tailored the building volumes in response to the site’s different adjacencies, moving down in scale, for example, toward the low-lying Brookline neighborhood, and peaking toward the site’s center with the 27-story tower.

In this type of dense urban development, transportation is often a limiting factor, since it demands so much public investment. The Fenway Center benefits from already-existing subway stops and the commuter rail stop Yawkey Station, which is currently undergoing a separate, state-funded expansion. Once the project is complete, the station will operate with net-zero energy use. The designers are taking advantage of a large south-facing wall on the planned parking garage to support photovoltaic panels designated to power the station.

“The barriers to entry are very high in Boston development,” said Rosenthal, citing the city’s tradition of community-based development input, a process that can take up to five years. “The secret sauce for breaking the log-jam,” he continued, “was getting everyone involved.”

Rosenthal had convincing metrics on his side, too. “Right now, the site pays no taxes,” he said. “But once we’re done, it will generate several million in tax revenues, and about $2 billion in economic development over the 99-year lease period. We’ve spent ten years trying to get to this point. I’m thrilled—totally thrilled.”