Each ring is fixed to the wall from 10 anchor points（定位點） to hold it in place against the force generated by trains

The rings - which are 9.4m (31ft) wide and 4.6m (15ft) high - are fixed to the wall of the tunnel （隧道）in Coquelles, near Calais, in northern France.
They were built in Lille and assembled（組裝） at the tunnel entrance over two nights by five rock climbers.

Their unveiling （揭幕式）was at a special event marking "20/12 Day" on 20 December.

Each ring is fixed to the wall by 10 anchor points to hold it in place against the force（力） generated （產生）by trains passing at up to 160km/h (99mph).

Showing unity

In March, a giant set of Olympic rings was revealed（顯示） at St Pancras International station in central London.

The station, a Eurostar terminus（終點） since 2007, forms a key part of London 2012 transport plans.

Organisers say high-speed Javelin trains will take visitors from there to the Olympic Park in seven minutes during the Games.

The 20m (66ft)-wide aluminium（鋁） structure is suspended（懸浮） in the station's vast main space.

It was the first of several sets of rings that will appear on key landmarks around the city in the run up to the Games in July.

The logo （標志）of five interlinking Olympic rings（奧林匹克環） was designed by the founder（創始人） of the modern Olympics, Pierre de Coubertin, and has been a symbol （象征，標志）of the Games since 1914.

Coloured blue, yellow, black, green and red, the rings represent（代表） five continents（大陸，洲） and are linked to show unity （團結）between the world's athletes in the spirit of the Olympic movement.

The manufacturing（生產，制造） and placement （安置）of the rings has been privately financed （贊助）by Eurotunnel, who have worked closely with（緊密合作） the Comité National Olympique et Sportif Fran?ais (the French National Olympic Committee).

Seb Coe, chair of London 2012, said: "The Olympic Rings are an iconic（圖標的） symbol, inspiring（鼓舞） athletes and uniting （團結）people around the world.

"To athletes they represent（代表） the culmination（頂點，高潮） of thousands of hours of training and reaching the highest level in sport. To visitors travelling from Europe they will excite and inspire them about the Olympic Games taking place in London, and demonstrate that we are ready to welcome the world in 2012."

The Mayor of London, Boris Johnson, said: "As the starting line（起跑線） for 2012 Olympic and Paralympic Games fast approaches （接近）we want to say loud and clear to all our European neighbours that London is the only place to be next summer."