Britain's Queen Elizabeth II arrives to unveil a plaque marking the 20th anniversary of the opening of the Channel Tunnel and the launch of international high speed rail services between the UK and mainland Europe at St Pancaras railway station in London on June 5, 2014. More than 330 million passengers and 65 million vehicles have gone through the tunnel since it opened to the public in 1994, travelling on high-speed train services and vehicle shuttles. AFP PHOTO / JUSTIN TALLIS        (Photo credit should read JUSTIN TALLIS/AFP/Getty Images)