On 25 December 1979, Soviet forces invaded Afghanistan.
Moscow was able to install a friendly government in a neighbouring country but at a price.
The invasion gave a common cause to an extraordinary alliance of radical Islamists in Afghanistan and around the world and to the neo-conservatives in the US.
It was a key battleground of the Cold War.
Washington provided money and arms including even Stinger missiles capable of shooting down Soviet helicopters.
But it was Islamic Mujahideen fighters who would fire them.
Among the many foreigners drawn to Afghanistan was a young, wealthy Saudi called Osama Bin Laden.
http://news.bbc.co.uk/2/hi/programmes/3951615.stm
