The disaster was unique. There was no collapse of a structure: it was the first example in the history of football ... of serious casualties inflicted by a crowd upon itself.

British Home Office report into the March 9 1946 Burden Park football stampede, where 33 spectators were crushed to death.

People often fail to perceive that a crowd of people tightly packed together constitute several tonnes of weight, which becomes quite dangerous if is constrained in a congested environment. A crowd tend to be more irresponsible and excitable than the individuals it is composed of, and less capable of identifying hazards and thinking itself out of danger. And it is a fine line for people to know in good time the difference between being uncomfortably crowded and being dangerously crowded.

Most victims of a stampede die of suffocation (specifically compression asphyxia), with other causes of death including head injuries, cardiac arrest and multiple trauma. The huge number of people involved and the difficulty for paramedics to reach the injured can mean that many victims are not treated in the vital golden hour.

Perhaps the most dangerous place for stampedes to occur is at Mecca and Mina in Saudi Arabia. Attracting the world's population of Muslims on their Hajj pilgrimage, there have been many occasions when the local authorities have been unable to control the flow of massive numbers of pilgrims, many of whom become highly emotional at the stoning the devil ritual. The worst incident occured in 1990 when an overcrowded pedestrian tunnel collapsed, leading to the panic that ultimately killed 1,416 worshippers.

Crowds also gather at sporting fixtures, and like religion, can attract the excitable. The Hillsborough disaster in Sheffield, Britain in 1989, where 96 Liverpool supporters were killed, was caused by the police deciding to open a second set of gates for spectators to enter just prior to a match starting. However the visitors were fenced in within a smaller portion of the Hillsborough stadium isolated from the home team, and the ensuing thousands who entered forced the people who were already at the front against a riot-proof fence. Similar soccer disasters have occured in Buenos Aires in 1968 , Kathmandu in 1988 and Accra in 2001.

Some musicians, including ACDC (in Salt Lake City), Pearl Jam (in Roskilde, Denmark), Public Enemy (in Nashville), Limp Bizkit (in Sydney), Eminem (in Glasgow) and The Who (in Cincinnatti) have been the performers at venues where deadly stampedes have occured. Of somewhat bad taste, a bootleg album recording of the concert where The Who played in 1979(and eleven fans died) was called 'Stampede'.

Often stampedes coincide with other disasters, and occasionally more people die as a result of the panic than from whatever deadly agent they are escaping from. The Guiness Book of World Records states that the worst stampede occured at an air raid shelter in Chongqing, China on 6 June 1941. After hearing the 'all clear' siren the Chongqing citizens left the shelter, but a further warning caused the crowd to scramble back against itself. On 30 August 2005 around one thousand Shia pilgrims were killed in a stampede at a shrine in Baghdad, precipated by the rumour that several Sunni suicide bombers were in their midst.

However bad planning before and during an event can just be as much to blame, and indeed poorly thought out strategies to mitigate against bad behavior like gatecrashing and hooliganism may even contribute to a disaster. 21 patrons at the E2 nightclub in Chicago died on February 18 2003 after trying to scramble from the effects of a mace canister fired off, possibly by a security guard trying to break up a fight between two women. Firemen cited many contributing reasons for the deaths, including the failure by management to control the number of people entering the club and having fire doors locked from the outside. Another tragic example happened at Victoria Hall theatre in Sunderland, England in 1883, where 183 children were crushed to death in a narrow stairwell that led from the gallery down to the stalls as they rushed to grab some free presents.

The World Health Organisation has a series of codes for deaths caused in stampedes, defined as 'Crushed, pushed or stepped on by crowd or human stampede', and is further categorised by the type of location where the death occured. The International Classification of Diseases had until 1997 deaths and injuries sustained from a stampede coded as W52 (codes W50 to W64 concern 'exposure to animate mechanical forces', such as alligator bites and being kicked by another person). It now is coded as E917.1, being 'Caused by a crowd, by collective fear or panic', although one wonders if it can be applied to stampedes where other emotional factors were at play, such as shoppers racing for the Boxing Day sales.