Trafalgar laws crew was low on food so they stopped on the nearest island which happened to be the island you lived on from the outside it just looked like a random forest but on the inside nobody from outside of the island knows,your island is special... someone or something...is protecting it,nobody can get inside or outside people on the inside of the island can't get off the island otherwise they'd be killed by the invisible barrier but that all changed the day Trafalgar law came