The arena that hosted the 2017 "Billboard" Music Awards opened  on what date?
2017 Billboard Music Awards: The 2017 "Billboard" Music Awards was held at the T-Mobile Arena in Las Vegas on May 21, 2017. T-Mobile Arena:  Opened on April 6, 2016, the arena is a joint venture between MGM Resorts International and the Anschutz Entertainment Group.
April 6, 2016