A man who climbed under the roof of the Dortmund stadium during Germany’s European Championship round of 16 match on Saturday was masked and carrying a large rucksack, according to video footage. The video, published by the website of English newspaper the Daily Mail, shows the man being arrested by police at gunpoint after the match against Denmark. Officers announced that the man was a 21-year-old from the German city of Osnabrück, around 120 kilometres north of Dortmund. Police said there had been no danger to spectators but did not reveal how he entered the stadium, what was in the rucksac…