Roanoke Island is off the mid-Atlantic coast of the United States, in North Carolina. In fifteen eighty-seven, more than one hundred people arrived from England to live on the island. Three years later, they were gone.
Today we revisit the mystery of whatever happened to America's "Lost Colony."
Is it okay to say the bold sentence in this way:
Today we revisit the mystery of what in the world happened to America's "Lost Colony."