US President Donald Trump suggested he might keep the Ultimate Fighting Championship cage-fighting arena being built on the lawn of the White House as a permanent fixture.The Republican compared the structure, which is being built for a night of cage fighting to mark the 250th anniversary of US independence – on Trump’s 80th birthday – to France’s Eiffel Tower which was supposed to have been dismantled 20 years after it was built in 1889.“We’re building something in front of the White House...