Near the center of Seoul, South Korea is Yongsan-gu, a vibrant district just north of the Han River.

It's the seat of the local U.S. military presence, which occupies the Yongsan Garrison, originally built by the Japanese. But as Seoul's urban sprawl engulfed the complex, South Korea and the U.S. reached an agreement to relocate troops by 2013.

The move created an urban tabula rasa, which was reimagined by some of the world's prominent architectural firms, including Skidmore Owings & Merrill and Norman Foster, in a design competition. But it was Daniel Libeskind, master planner for the World Trade Center, who would win with an archipelago of tower islands, anchored by a 150-floor building that would be second-tallest structure in the world.

The parallels between the new Yongsan development, branded as DreamHub, and the World Trade Center are striking. They are a set of towers set within green space and framed by rivers, both offering visions for 21st century urbanity. A master plan provides a sweeping, bird's eye view of the future. But just as Libeskind's plan in Lower Manhattan shifted with the entrance of new architects, his Seoul project continues to evolve. And while DreamHub lacks the symbolism and monumentalism of the Trade Center, the last week has seen it draw nearly as much controversy.

Dutch firm MVRDV revealed The Cloud earlier this month, a set of two towers with a pixelated cloud that form sky bridges of green space, shops and other facilities. The irregular stack of blocks is reminiscient of Moshe Safdie's Habitat 67 in Montreal, but in an irregular arrangement that seems to defy gravity.

But for many Americans, the design echoed the 9/11 attacks, with the billowing midsection suggesting explosions of debris. There were immediate calls to scrap the design and critics cast the architects as terrorists or hungry for publicity.

MVRDV was taken aback.

The Cloud was designed based on parameters such as sunlight, outside spaces, living quality for inhabitants and the city. It is one of many projects in which MVRDV experiments with a raised city level to reinvent the often solitary typology of the skyscraper, the firm said in a statement, apologizing--but not retracting--the design.

Indeed, the debate appears to swirl not so much around architectural merit, but rather intent and impression. As the Washington Post's Phil Kennicott wrote, The controversy seems part of a larger cultural effort to make the events of Sept. 11, 2001 somehow sacred, to use the meaning of the terrorist attack for larger, more overbearing cultural control. He noted that architects have long sought to break the conventional structure of buildings, and to explode a building could mean to unlock potential through bold design. Furthermore, he said, any reference to 9/11 was not necessarily disparaging, but could in fact be a method of catharsis.

A distinct parallel to to The Cloud is the Islamic cultural center and mosque, Park51, that is planned a few blocks north of the World Trade Center. The politicization and emotional fury towards both the two projects was rapid and explosive. However, one is planned for the other side of the world and judged based on aesthetics, while the other was targeted for its location and usage, rather than its honeycomb form.

The two projects share a particular form of not in my backyard mentality, or NIMBYism, that trascends geography. Other architectural controversies tend to focus on density and location. And, even if a design is uninspired, it usually provokes no more than resignation or indifference, aside from those who are directly involved. But the 9/11 attacks were such a global trauma, documented across the world, that any reminder remains painful even a decade later.

However, even the original World Trade Center was marked by its own controversy. In order to build such a vast office complex, the Port Authority demolished blocks of local businesses and residences in the area, known as Radio Row. The project had no formal land use review and even managed to upset the city's major landlords, who feared it would dump an unneeded glut of subsidized office space onto the market.

At the same time, its design was indebted to globalization and the free flow of ideas. Minoru Yamasaki, the late Japanese-American architect of the twin towers, was strongly influenced by Islamic architecture. Yamasaki designed the Dhahran Airport in Saudi Arabia, which featured similar pointed arches to the ones that made up the bases of the towers. He would call the plaza a mecca, a great relief from the narrow streets and sidewalks of the surrounding Wall Street area, and a parallel has been drawn between Fritz Koenig's sculpture The Sphere, which stood in the plaza prior to the attacks and the Kaaba in the center of Mecca.

During the boom, Daniel Libeskind proposed a soaring tower for Elad Properties near Madison Square Park, with exposed greenery at various intervals. Bloomberg's architecture critic said, if built, the project would be a crude and unavoidable reminder of the horrors of 9/11, describing the gaps as gashes in its facade. That project appears to have been scrapped because of the downturn, and both The Cloud and Park51 could meet similar ends from a developer's reluctance or lack of financing. But by enduring criticism and defying risk, the architects behind each project are taking steps that are essential for design as a whole to move forward.