9/11 conspiracy theories: 10 years later
Now has over 600 comments.
It may be 10 years since the attacks in the US on 11 September, but conspiracy theories have not faded over time, says Mike Rudin.
Numerous official reports have been published since the Twin Towers fell, but just when a piece of evidence casts doubt on one theory, the focus then shifts to the next "unanswered question".
Here are five of the most prominent 9/11 conspiracy theories circulating in online communities.
1. Failure to intercept the hijacked planes
2. Collapse of the Twin Towers
3. Attack on the Pentagon
4. The fourth plane - United Airlines flight 93
5. Collapse of World Trade Center Building 7