What was held at the United Center in Chicago, Illinois on June 23-24, 2017 and resulted in Sebastian Aho playing under contract as a prospect of the New York Islanders?
Sebastian Aho (ice hockey, born 1996):  Aho was drafted by the Islanders, 139th overall, in the 2017 NHL Entry Draft. 2017 NHL Entry Draft:  The draft was held from June 23–24, 2017, at the United Center in Chicago, Illinois.
i don't know