|WTC1's The Spire
One of the peculiarities of 9/11 is "The Spire". When WTC1 first 'collapsed', a portion of the skyscraper's core remained standing. This portion of the core stood naked for about 15 seconds, at roughly 2/3 the tower's height. In other words, this skinny steel spire briefly stood more than 600 feet tall!
The WTC1 Spire
The Spire (magnified) (1.4M QuickTime6)
In some close-up shots, where the tip of the spire simply disappears from the frame, it can appear as if the solid steel simply went poof. However, in this view of the WTC1 'collapse', it appears that the spire fell (or at least started to!) as one solid mass.
No one has ever explained how such a tall skinny column could fall straight down (rather than topple over) along the path of maximum resistance like that.
BTW, make sure you don't focus on the spire so much that you fail to take note of that incredible pyroclastic "dust cloud"!
That's not an ordinary cloud of dust. Clouds like that are not the normal outcome from lots of supposed pulverization (which consumes energy, it doesn't release it). (Such spectacles do not result from "controlled demolition", either.) Such pyroclastic flows - large distinct regions of vastly different temperature/density/opacity - had previously only been seen following volcanic eruptions (and nuclear blasts), indicating that an unexplained, unimaginably huge release of heat energy accompanied the unique destruction of the razed buildings.
The full video's audio track is also interesting. It was recorded early afternoon (MDT) on 9/11, off the air, from CBS TV affiliate KKTV.
For another glimpse of The Spire, that was shown on TV on 9/11 but never again, click here