WASHINGTON—America’s semiquincentennial birthday celebration kicked into gear June 14 with the Ultimate Fighting Championship’s (UFC) Freedom 250 Fight hosting seven matches on the South Lawn of the White House. To kick off proceedings, President Donald Trump and UFC President and CEO Dana White walked through the White House grounds past the new Presidential Walk of Fame before greeting the crowd from the Truman Balcony. Three-time grammy winner artist Zac Brown Band sang the national anthem, joined by the U.S. Marine Band, while a 12-plane formation of Navy Blue Angels and Air Force Thunderbirds flew overhead. “This will be the greatest show on earth,” Trump said while previewing the stage in May....