Below are the temperatures of hot spots in the World Trade Center wreckage five days after the buildings came to ground:

World Trade Center Hot Spots - September 16, 2001 Hot Spot Temp ºC A [WTC 7] 727 B [WTC 7] 557 C [WTC 1] 627 D [WTC 1] 517 E [WTC 1] 437 F [WTC 2] 427 G [WTC 2] 747 H [WTC 2] 547 Source: USGS Spectroscopy Lab

Note that WTC 7 and WTC 2 had hot spot temperatures in excess of 700°C five days after the buildings came down.

The following table gives approximate metal temperatures by color.

Lead (Pb) Melts Faint Red Blood Red *Aluminum Melts Medium Cherry Cherry Bright Cherry Salmon Dark Orange Orange Lemon Light Yellow White *Steel Melts *Iron Melts *Thermite (typical)  °F 621 930 1075 1221 1275 1375 1450 1550 1630 1725 1830 1975 2200 ~2750 2800 >4,500  °C 327 500 580 660 690 745 790 845 890 940 1000 1080 1205 ~1510 1538 >2500 K 601 770 855 933 965 1020 1060 1115 1160 1215 1270 1355 1480 ~1783 1811 >2770 Red hot metal being retrieved from the WTC wreckage.

The wreckage contained molten metal.

When first erupted from a volcanic vent, lava is a liquid at temperatures from 700 to 1,200 °C (1,292 to 2,192 °F), so the following gives an idea of the heat of the hotspots.

Is it any wonder the fire took months to extinguish?

Conventional fires cannot account for this.

Thermite can.