Madagascar is the fourth largest island in the world. It's located off the southeast coast of Africa. Madagascar is home to many animal and plant species that can't be found anywhere else on the planet. Around 80% of the plant and animal life on the island can only be found on Madagascar.reenland is part of the continent of North America, but politically has generally been part of Europe through the country of Denmark. Great Britain. Great Britain is the ninth largest island in the world and is the largest island in the British Isles.