Barack Obama's big speech on tomorrow night will be delivered from an elaborate columned platform resembling a miniature Greek temple, it has been revealed. The stage is similar to structures used for rock concerts and has been set up at the 50-yard-line, the midpoint of Invesco Field, the stadium where the Denver Broncos' American football team plays. Up to 80,000 supporters will see Mr Obama appear from between plywood columns painted off-white, reminiscent of the White House, to accept the party's nomination for president. He will stride out to a raised platform to a podium that can be raised from...