Reconstruction work at the World Trade Center in New York has required a level of coordination and cooperation that would demoralize even the largest of integrated design firms. This is especially true of the transit hub, which reaches out to connect the various buildings on the site with multiple train lines traversing Lower Manhattan.

The way it is told in the halls of AECOM—the company in charge of the hub’s engineering, site preparation, PATH facilities, security, wayfinding systems, and more—getting a handle on Santiago Calatrava’s vision for the project proved to be a tall order for the transportation experts assigned to the job. The Spanish architect may be renowned for his clarity and eloquence, but his high-flown presentations proved to be Greek to these men and women who are more accustomed to planning circulation paths and calculating load patterns. Luckily, AECOM had a solution to this communication breakdown. It reached into the voluminous folds of its global network and pulled out a few architects—employees of a former DMJM office in Arlington, Virginia, to be specific—sending them north to act as emissaries and interpreters between the silver-tongued architect and his iron-eared collaborators. The result, reportedly, has been a smoother integration of the project’s sculptural and functional design elements.

The past decade has seen a proliferation of large and complex projects that draw upon global resources both intellectual and material. The World Trade Center is but a small example. Entire cities are being built from scratch in the wilderness of China. Luxury developments stocked with the finest in convenience and culture are rising from the deserts of the Middle East. As the projects have gotten bigger, more all- encompassing in their scope, and located in what were once far-flung corners of the world, the firms that design and build them have followed suit. No one company has taken this impulse further than AECOM. With 45,000 employees and offices on every continent, this megalith has assembled expertise in every area necessary to design, build, and fuel a modern city. Its reason for being— ”to make the world a better place”— is as magnanimous as it is grandiose; its purpose—”to enhance and sustain the world’s built, natural, and social environments”— is as singular as it is vague.

If you have never heard of AECOM, or if you have only just recently become aware of the name but aren’t certain what exactly it is or does, you are not alone. Up until last year, AECOM was little more than a holding company, a fairly abstract entity that held together a loose consortium of design, engineering, and project management firms operating in their own sectors and under their own names. Its genesis dates to the late 1980s, when Kentucky-based Ashland Oil, looking to diversify its business, purchased five large architecture and engineering companies, creating a design firm called Ashland. The oilmen, however, soon lost interest in this line and allowed the companies to buy themselves back. In 1990, those five firms, including architecture giants DMJM and Frederic R. Harris, established the AECOM name, which stands for architecture, engineering, construction, operations, and management. From that moment forth, the growth did not cease as more and more firms were acquired and more and more disciplines were incorporated. In 2007, AECOM became a publicly traded company, and today it is one of America’s biggest firms with more than $6 billion in annual revenue.

This mushrooming to such gargantuan proportions was not conducted randomly, of course. Rather, AECOM leadership singled out companies for acquisition that filled a market or geographical niche not yet represented in the portfolio. To use architecture as an example, shortly after 1990, Spillis Candela of Miami was acquired for its expertise in civic and courthouse design. Hays Seay Mattern & Mattern of Virginia were brought aboard for their cultural experience. Chinese firm CityMark was purchased because, well, they were in China. EDAW was sought out and wooed for its highly developed global planning and landscape design practice. Most recently, Ellerbe Becket was merged for its strength in the Midwest and expertise in sports and healthcare typologies. That last acquisition more or less rounded out AECOM’s portfolio, giving it influence everywhere on the planet and skill in everything imaginable, but that doesn’t mean that it will stop its search. The company is always looking for smoothly operating integrated design firms, and would particularly like to increase its competence in airport design.

AECOM made its official debut in October 2009. “Two years ago it was decided to reorganize the company,” explained Tom Fridstein, an AECOM executive vice president and head of global architecture. “It had grown to such a size and there were so many companies we wanted to rebrand to one identity.” The company’s many disciplines were organized into five main business lines: Planning Design and Development, which includes architecture, engineering, landscape design, project management, and economics; Transportation, with everything from airports to bridges and tunnels; Energy, both generation and transmission; Environmental, from brownfield restorations to carbon footprint assessments; and Water, with wastewater treatment facilities, desalination plants, you name it. All of the business lines share a common financial structure, business development and marketing department, data systems, and, of course, human resources, as was shown in the example of the World Trade Center.

It is difficult to conceive of how such a many-limbed beast would even begin to function with one mind, but AECOM has devised a fairly simple matrix to help navigate its global business. On one axis of this matrix are geographical regions, and on the other are business lines. While local offices are largely in charge of developing and maintaining their own business—as with many firms, most of AECOM’s clientele are repeat customers, legacy clients of the legacy firms—the company’s top leadership, which is mostly made up of architects and engineers, is in charge of looking across geographical boundaries and market sectors to locate opportunities and assign resources as needed. This gives AECOM an edge over firms that may not have such a deep pool of talent to draw from, or a network of offices around the world. “If you’re going to be global, your expertise is not going to exist in every location. That’s where collaboration comes in,” said Jon Miller, an AECOM senior vice president in the Arlington, Virginia, office. “If you have a project in Kuwait, but not the right people for it on the spot, you can draw from other regions and establish the right talent in the right location. The global market is changing,” he added. “Today in Dubai they want people there on the ground. It used to be you could do it all from the U.S. and just send the drawings. Now clients want people who are committed to the region.”

This global reach is also beneficial for AECOM clients that want to expand their business overseas. Rick Lincicome, an AECOM senior vice president who has come in from Ellerbe Becket, said that one of his old clients, a hospital based in South Dakota, wanted to expand its business outside of the U.S. They were thinking they would have to find another architect to do the job, one with more global experience. “We had to educate them that we actually had global reach,” said Lincicome. “Joining AECOM is going to be great for that client.”

Though enormous, AECOM tries to balance its portfolio with both large and small projects. “The challenge today is being able to operate locally and globally, to work on a small level and be able to scale up,” said Fridstein. “We operate like any other firm. We have the benefit of having a huge amount of people, but we can put together a team of two people or 200 people depending on the size of the project.” And though of its 45,000 employees only 4,000 are in the Planning Design and Development division, of which about 1,500 are architects, it wishes to be seen as a design firm. “There’s a fear that these large firms put design as a subset to construction,” said Miller. “Not so here. We are very much about design. The upper management is made up of designers. When I look up I see architects above me, and that’s comforting.” If these desires sound a bit contradictory, that’s because they are. How can an entity be both large and small, both dedicated to design and composed mostly of management types? Scaling project teams down to meet the demands of a given project is one thing, but operating like a small business with all of the cultural trappings of a boutique design house, and perhaps the guiding force of a single genius, is something quite different.

What this boils down to is a bit of a personality crisis—if having multiple personalities is a crisis. The public launch of AECOM fused a multitude of businesses under one name, but it didn’t create a single culture, at least not yet. For the time being, the firm seems happy to have those different voices all under the same roof. “When we merge with a company, it’s because we think they’re doing something very good,” said Fridstein. “We don’t want to lose what that is. I’ve seen other firms buy a company and dismantle it. Once they do that, they lose the value they’ve acquired.” The large size and investment in a wide range of markets helps make the company stable, as when one sector is down, those that are up can carry things along. And the fact that it is publicly owned, without one defining principal at the top handing down the gift of their brilliance, provides for smooth changes of leadership. “When you’re this large, you can’t have one personality. Our very purpose is to be beyond one defining feature,” said Lincicome. “We are AECOM, we can do anything.”