This New York landmark was once the world's tallest building at 1,250ft and has been a tourist attraction since it first opened. Tales about the building's early years abound--its spire, for instance, was meant as a mooring point (not a landing strip!) for dirigibles flying into the city. The architectural design was completed in two weeks as it borrowed heavily from another earlier project in the office, the construction documents in about 6 months, and construction itself in two years. The Empire State Building was recently voted America's most Favorite building in a 2007 AIA survey. It has New York City landmark Status for both the exterior and the lobby floor. The American Society of Civil Engineers voted it as one of the Seven Wonders of the World. In 2010, in partnership with the Clinton Climate Initiative, the building was retrofitted to improve energy efficiency and financial performance which is projected to save 38% of the building's energy use.