Photostory - The footsteps of terror

Early forms of terrorism focused on targeted killings of high profile individuals. One of the most famous was by Gavrilo Princip, pictured here on the right having been arrested for the murder of Archduke Franz Ferdinand and his wife. The killings took place in Sarajevo on June 28, 1914. By 28 July 1914, the First World War had begun. (© Reporters)

In the modern era, anti-terrorism efforts have had to tackle larger scale terror attacks, such as those involving aircraft. But the installation of metal detectors in international airports in 1973 led to less hijackings - but more terror attacks using other means (see Bjorn Lomborg's article for more details). (© Reporters)

The seminal moment in modern terror attacks came on the morning of September 11, 2001. Above is the World Trade Centre's Vesey Street staircase - the only piece of the buildings which stood in exactly the same place following the attacks. (© AP / Reporters)

One of the main challenges facing counter terrorist operations is the will of terrorists to sacrifice everything. Above is Mohammad Sidique Khan. He was born in the UK and taught at a children's primary school. He had a one year old daughter - his wife was heavily pregnant with his second child. On July 7, 2005, he blew himself up on a London underground train as part of a coordinated set of suicide attacks that killed 52 people.

But, just like 100 years ago, terrorists still remain adept at carrying out targeted assassinations of key people. Benazir Bhutto, pictured here seconds before her death, had promised to take a tough line on the Taliban in the Pakistani elections. In one of her last interviews, she said: 'I am what the terrorists most fear - a female political leader trying to bring modernity to Pakistan. Now they're trying to kill me.'

The trail of funding for terrorists often leads back to drugs. And the trail of drugs often leads back to Afganistan. The country provides 90 per cent of the world's opium. About 10 kilos of opium can make one kilo of heroin. The street value of a kilo of heroin in London is around 75,000 euros. In 2007, about half of Afghanistan's opium produced 666 tonnes of heroin or morphine export. (© Photos Stock Exchange)

In their bid to create disorganisation, terrorist groups have often become more organised. This picture shows an [i]al Qaida [/i]prison and training facility uncovered near Baghdad in March 2008. Prisoners were caged, handcuffed, tortured. Interrogation books written in Arabic were also discovered. (© AP / Reporters)