[TallFan]

The best location for an outdoor observation deck might be on top of Tower 3, think about it... WTC 1 has the spire and the lights taking up space, so no room for too many people, plus safety concerns. Tower 2 has no roof in the conventional sense and Tower 4 is the shortest of the bunch. Tower 3 would be perfect, central to the entire World Trade Center complex, surrounded by all the other buildings, you would truly feel a part of the whole experience. This could be an alternative addition to the indoor observation deck in Tower 1. Now if they just build Tower 3 to it's full planned height.