Donald Trump's planned UFC event at the White House is drawing major backlash as a massive octagon arena rises on the South Lawn ahead of the June 14 celebration, which coincides with the U.S. President's 80th birthday. Critics have branded the spectacle a 'circus', while supporters call it a historic part of America's 250th anniversary festivities. The event also faces a legal challenge over the use of federal land and environmental concerns. Here's everything we know about the White House UFC showdown, the controversy, ticket demand, fight card and growing political debate.