The World's developer is Nakheel Properties, and the idea was envisioned by Dubai's ruler, Sheikh Mohammed bin Rashid Al Maktoum. Van Oord and Boskalis, two Dutch (joint venture) specialist businesses, completed the building. The Palm Jumeirah was also built by the same firms. Two other islands are under construction, and another three have been cancelled. Sheikh Mohammed said at the time of announcement: "We are very happy with this new project. It is a great opportunity for us to test our capabilities before we start work on the next big thing for Dubai." The world islands were inspired by Dubai's geography: they reflect the layout of the city-state, with seven islands based along the coast and two connected to the mainland by bridges. Each island has a different theme or feature intended to appeal to visitors' senses: adventure for those who want to go hiking or biking, relaxation for people who like fishing or diving, culture for art lovers, and luxury for anyone who enjoys shopping or dining out. They're also designed to protect their inhabitants from the sun and wind. For example, everyone living on the islands will be able to walk around without shoes, because the sand on each island is separated from the others by a solid surface - in this case, water - which prevents it from being eroded by rain or wind.