May 11, 2012 -- With the Olympic torch lit in Olympia Thursday and on its way to London, the countdown to the opening ceremonies of the 2012 Summer Olympics has officially begun. (Click here for a map of the torch relay route.)
Over its 70-day journey through the United Kingdom, the Olympic flame will travel to 95 percent of the population of the United Kingdom. However, the details of the final leg of the tour are being kept secret until the relay officially begins on May 19.
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The 8,000-mile relay throughout the United Kingdom will include the participation of around 8,000 torchbearers. An average of 115 torchbearers a day will carry the Olympic flame.
As HowStuffWorks.com's Stephanie Watson explains, those participating in the torch relay must be able to carry the torch for at least a quarter mile. Being able to walk isn't necessary as the handicapped are encouraged to participate. Beyond that single requirement, torchbearers are selected by the Olympic sponsors and organizers, and anyone meeting those prerequisites can apply to carry the torch prior to the official selection.
The Olympic Cauldron, however, is typically lit by a former athlete, marking the start of the games.
Past participants include current or former athletes, celebrities, politicians, media personalities and more. In fact, one of the torchbearers for this year's relay is a British woman named Diana Gould, who will be celebrating her 100th birthday as she carries the Olympic torch.
Gould appears on the right of this photo beside Mayor Boris Johnson. Dominic John MacGowan, pictured on the left, is the youngest torchbearer at age 11 participating in the relay.
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Although it might seem simple enough to design a metal stick to carry a flame, the Olympic torch must meet a stringent set of technical and aesthetic requirements.
The torch must be able to maintain the flow through a variety of weather conditions, including high wind, rain, snow and extreme heat, as explained by The Olympic Museum. Torches also must be designed to carry a backup flame on the chance that the fire is extinguished.
This year's design, by Edward Barber and his partner Jay Osgerby, is a triangular, gold-colored torch with 8,000 holes, one for each runner participating in the relay.
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As London's mayor Boris Johnson recently explained on a visit to local schoolchildren, the Olympic Torch harkens back to ancient Greek mythology.
The Olympic Flame celebrates Prometheus bringing the gift of fire to humankind, having stolen it from the god Zeus. Actresses playing priestesses at the Temple of Hera produce a flame for the lighting ceremony by using a parabolic mirror and using reflected light from the sun to produce fire.
The 1928 Summer Olympic Games held in Amsterdam marked the first time that the Olympic Torch was used in the modern era.
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While the lighting of the Olympic torch itself might have its roots in Greek mythology, the torch relay in the modern Olympic Games has a darker past. In fact, as The Atlantic's Max Fisher notes, it was the Nazis who, prior to the 1936 Summer Olympic Games, invented the relay.
Devised by Carl Diem, the secretary-general of the 1936 Berlin Games, the relay was meant to bolster the myth of Aryan supremacy. The symbol of the flame traveling 1,500 miles from Athens to Berlin as a means of reinforcing "the idea of a shared Aryan heritage between the ancient power and the new one." In fact, the flame passed through a number of countries that Nazi Germany would soon invade, annex and occupy during World War II.
Despite its darker origins, the relay has been recast as a token of international brother- and sisterhood rather than a propaganda tool of an aspiring global hegemon.
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The 1948 Summer Olympic Games, the last time London hosted the Olympics, marked the first games since the Nazis hosted prior to the outbreak of World War II.
Dubbed the "relay of peace," the Olympic Flame started in Greece in accordance with tradition. Prior to assuming the Olympic Torch, Greek Corporal Dimitrelis stepped forward in military uniform, which he removed to reveal the athletic clothes, symbolizing an end to hostilities.
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As the Olympic Torch Relay became a tradition, each host nation left their mark on the event by creating their own version of the torch. Every design has had its share of supporters and critics. But there was at least one case in which the torch was undeniably flawed.
The 1968 Summer Olympics relay in Mexico City used a torch that proved dangerous. Shortly after this photo was taken, the torch exploded, injuring both men pictured here.
The rest of the relay, however, proved to be a success. Intended to be a celebration of the New World, the relay course retraced the steps of Christopher Columbus, and even included a stop to the Great Pyramid of the Moon in Teotihuacan, where the flame was used in an Aztec fire ceremony.
In order to get from the lighting ceremony to Olympics host nations around the world, the Olympic torch relay can't rely entirely on runners. Throughout its history, the torch has been carried by jet, boat, horseback, dogsled, camel, snow-bike skidoo and more.
But for the 2000 Summer Olympic Games in Australia, the Olympic Torch Relay went underwater for the first time. Torchbearers carried the Olympic Flame past the Great Barrier Reef. Powered by a chemical formula that produced enough oxygen and nitrogen to maintain the flame, the torch was carried by marine biologist Wendy Craig Duncan and remained submerged a full three minutes.
The torch relay for the 2008 Summer Olympics Games held in Beijing turned out to be one of the most controversial in recent history. Protests against the Chinese government over the issues of human rights, democracy and Tibet spilled into the ceremony.
Although the torchbearer travels with a caravan and security, one protestor, Ian Harold Brown, managed to briefly seize hold of the torch as it was traveling through London. As the protests began to overshadow the event itself, the relay was cut short in order to prevent further disruption.
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