Barrier Reef. reef system off of Belize second largest barrier reef in the world Barrier Reef longest barrier reef second largest barrier reef in the world 2nd longest barrier reef Barrier Reef. Belize coral reef system second longest barrier reef barrier reef Barrier Reef. Belize coral reef system Belize Barrier Reef barrier reef, Barrier Reef. Belize Barrier Reef Belize coral reef system Belize Barrier Reef Ambergris Caye, Belize