Yesterday’s rush hour chaos in Midtown was an explosive reminder that twenty-first century sustainable building practices are meaningless in the absence of reliable infrastructure able to support a dense urban environment. While Con Edison is spending $20 million this year to maintain New York City’s steam pipes, much of Gotham’s infrastructure- from utilities to mass transit- was built well over a century ago. In fact, the American Society of Civil Engineers estimates that an incredible $1.6 trillion would be necessary to upgrade U.S. roads, bridges, and water systems to an acceptable condition. Cities like New York are sustainable because of their incredible density. While modernizing our utility and mass transit systems is not as sexy a story as the next LEED Platinum office tower or residential green roof, green building proponents must make these efforts a priority. Otherwise, they’ll risk seeing the backbone of urban environments they hope to make even more sustainable suffer the type of damage- or worse- that Midtown witnessed on Wednesday.