the twin towers were brought down with explosives – in a controlled demolition style.
but not maliciously.
All buildings over a certain height in Manhattan are hard-wired with explosive charges, so that the building can be sacrificed if the structure becomes catastrophically damaged.
imagine how bad it was when the twin towers collapsed, now imagine how bad it would have been if the towers had fallen sideways, not collapsed vertically.
just think, for every new-york skyscraper there is a remote-destruct button…
(better to bring a building down more-or-less within it’s own foot print, than allow it to fall sideways: TIMBER!)