WTC 7 was certainly struck by something.  It was struck by giant chunks of the North Tower and that's what caused the fire.    It had a gash all the way down the side of the building.  It had a gash at one of the corners started about 19 stories up.  18 stories.  http://4.bp.blogspot.com/-wwslje9VZ7A/UjBnz2C-sMI/AAAAAAAABfY/FTSnWfr6m-E/s640/June2004WTC7_Page_16_cropped.jpg These did not cause the collapse but affected how the building fell. WTC 7 was a massive buiding that suffered a massive fire for hour and hours.  Well before WTC 7 fell NYFD noted that the corner of the building was bulging out and you could hear sounds of creaking metal.  That is a sign of a building that has lost structural integrity and and will fall. https://www.firehouse.com/home/news/10544364/911-issue-introduction-part-vi  also we were pretty sure that 7 World Trade Center would collapse. Early on, we saw a bulge in the southwest corner between floors 10 and 13, and we had put a transit on that and we were pretty sure she was going to collapse. You actually could see there was a visible bulge, it ran up about three floors. It came down about 5 o'clock in the afternoon, but by about 2 o'clock in the afternoon we realized this thing was going to collapse.  By the way the much shorter WTC 4, 5 and 6 also suffered collapses that day. WTC 4 and 6 suffered from massive debris impacts.    WTC 5 also hit by debris, but it experienced a fire-induced structural collapse that day.  A thousand square meters between floors 4-8 collapsed due to fire.  It did not suffer a progressive collapse where this collapse effected the entire structure, like 7 did. http://911research.wtc7.net/mirrors/guardian2/wtc/fig-4-19.jpg http://911research.wtc7.net/mirrors/guardian2/wtc/fig-4-20.jpg You can see beams deformed from the fire here towards the left. http://911research.wtc7.net/mirrors/guardian2/wtc/fig-4-14.jpg Here's a column that partially buckled. http://911research.wtc7.net/mirrors/guardian2/wtc/fig-4-17.jpg BTW, we have had yet another building collapse due to fire the other day in Brazil.  Happened two months ago. https://www.youtube.com/watch?time_continue=23&v=XwoBRHDLxdo