1. Largest manmade island in the world - Palm Jumeirah island in Dubai consists of a trunk, a crown with 17 fronds, and a surrounding crescent island that forms an 11km long breakwater. The island is 5 by 5km and its total area is larger than 800 football pitches. The crown is connected to the mainland by a 300m bridge and the crescent is connected to the top of the palm by a subsea tunnel. The island doubled the length of the Dubai coastline.