The World Trade Center twin towers have gone.

If we pay some attention to the TV and newspaper, we will notice that people day something like that

1) The North Tower collapsed.
2) Both towers collapsed vertically.
3) Oh, my God! The tower comes down!

The word "collapse" has a typical usage in describing a person falls down suddenly because of some illness like heart-attack. For instance,
we may say somebody collapsed. In one words, if I hear saying somebody collapsed, I will immediately think he/she got a heart attack.