It's been 18 years since the horrors of September 11, 2001, when the two twin towers of the World Trade Center in New York, USA, were hit by a terrorist attack.

A doctor, witnessing the tragic terror experienced by the American people, hurried to the ruins of the twin towers and photographed the first moments after the attack that left about 3,000 victims.

Just hours after the devastation, the whole country was in dreadful chaos. Thousands of construction workers, firefighters, police and emergency workers were offered to help during the early days.

The doctor was one of the first to testify through photos the apocalyptic footage under the rubble.

Thousands were still trapped inside the rubble, while dozens more were being rescued every minute.