Of all the anomalies surrounding the 9/11 attacks, the collapse of WTC7 is perhaps the oddest. Not having been struck by any major pieces of debris, and not appearing to have any major fires in progress, it suddenly collapsed many hours after the second tower-airplane collision, exhibiting many characteristics which at least one expert has identified as those of a controlled demolition.
This is especially odd in that the building was the site of a city emergency control center (moved there in 1998) and thus was believed to be especially rugged: "Administration officials [...] said it could survive some bombs, would be impenetrable to gunfire and have a closed air circulation system to prevent the influx of gas. Its telecommunications equipment, they said, could operate even after a nuclear blast." 
Main Anomalous Details of Collapse
- not hit by any major debris
- no major structural damage
- ...except that Barry Jennings testified to an explosion which took out the lobby, before either of the twin towers fell
- no major fires
- delay of many hours between impact and collapse
- clean, vertical collapse
- collapsed from the bottom
- very close timing of collapse - middle began first, then outer edges
- collapsed into its own footprint
not hit by major debris
WTC7 did not suffer either airplane impact or severe fire. (We have not as yet uncovered any videos or photos of the back side of WTC7 before collapse, but none of the front-side videos show anything more than smoke rising from the back and a few isolated fires of normal intensity. If the official story concludes that there was significant fire damage, it needs to produce the evidence to support this conclusion.
Note that several other buildings around the twin towers (e.g. WTC5, WTC6) were damaged far more extensively than WTC7 but remained standing.
no major fires
WTC7 collapsed about 8 hours after the impacts, so a sufficiently hot fire would have had time to melt steel – but this would have required it to be absolutely engulfed in unusually hot flames (over 1000°F hotter than normal for a building fire, and never yet encountered in a steel-frame building fire) – which is not at all the case. Videos of WTC7's collapse show virtually no fire on one side, so any melting would have had to be on the back side – in which case it should have collapsed asymmetrically in that direction. WTC7 collapsed straight down.
Note that with the sole exception of the three collapsed buildings on 9/11 (WTC1, WTC2, and WTC7), no steel-framed building collapse has ever been attributed to fire, nor has any fire in a steel-framed building resulted in collapse -- despite many far worse fires than those witnessed on 9/11.
collapsed from the bottom
Unlike the explosive, top-down collapses of the twin towers, the collapse of WTC7 clearly begins near the bottom of the building (unfortunately out of sight of all recordings and photos uncovered so far) – a signature of a well-executed controlled demolition.
Perhaps there was somehow a very hot fire at the bottom levels, out of view of any of the recordings or photos. In this case, there should have been heavy smoke coming from all sides, and the collapse still would not have been as perfectly even and smooth as it was; more likely, the building would have tipped in one direction or the other as structural members on one side or the other gave way first. Symmetrical demolition is very difficult, and can only be done reliably by skilled experts.
- Why was there such widespread certainty that WTC7 either had collapsed or was about to collapse (e.g.   ) many minutes before it suddenly did so? Why hasn't there been any kind of investigation to clear up what is most likely an innocent mistake made on a day of unprecedented chaos?
- Why is WTC7 not mentioned in the official 9/11 Commission Report?
- Why were there apparently no efforts to fight the relatively minor fires in WTC7?
- Has anyone attempted to track down the individuals whose observations made prior to collapse are quoted as evidence, to find out if they agree with the interpretations of their quotes?
- interview with Controlled Demo Expert Danny Jowenko giving his firm opinion that WTC7 was brought down on purpose
- a related article includes links to about a dozen YouTube clips of WTC7 coming down (haven't actually looked at these yet, but certainly video clips I have seen confirm that the collapse was from the bottom and that the center started sagging fractions of a second before the whole building went smoothly down)
- 2005/09/12 [L..T] WTC7 Collapse: The Real Story (not tinfoil) “I see a semi-regular appearance of the idea that the WTC7 building (part of the WTC complex but not one of the Twin Towers) collapsed due to deliberate demolition rather than due to damage from the Twin Tower collapses. This is pretty implausible so I did some internet research to find out why so many people believe it and what actually happened.”
- WTC7.net: The Collapse of WTC Building 7
- Photographic Analysis of Damage to WTC7 and Critical Errors in NIST's Estimations
- 1998-06-14 Mayor Defends Plan to Build Crisis Center (should be moved to WTC7 page, when that has been created)
- WTC 7 Before Collapse: briefly shows one side of WTC7 after attack but before collapse, with minor fires visible.