The Palm Islands are the largest artificial islands in the world and are under construction in Dubai, in the United Arab Emirates. They are being developed as tourist, leisure, and residential resorts, and will increase the coastline of the country by 120 kilometres. After four years of planning and careful consideration of the environmental issues, construction started in 2001. Dutch engineers with experience of reclaiming land from the sea were employed in the building of the first two islands. The site for all three islands is an area of the sea where the water is not very deep. Sand is taken from the seabed and sprayed into the construction site. Although the shallow water _ this process, the islands are still very exposed to the currents and tidal movements of the sea. Rocks are used to hold the sand in place resulting in a large crescent   structure. This acts as a breakwater and protects the islands from the sea. The first two islands are in the shape of date palm trees and consist of a trunk and 17 frond, or leaves coming off the trunk. The first island, named Palm Jumeirah, has three five-star hotels in the trunk, and luxury homes in the leaves. It is astonishing that when these homes went on sale in 2004, they were all sold within three days. The second palm, Jebel Ali, was started in 2002 and is designed to be an entertainment centre. Six marinas   are planned, with a water theme park, and homes built on stilts   in the water. The Palm Deira planned to be the largest of the three islands, with a length of 14 km and a width of 8.5 km, an area larger than the city of Paris. It will consist of residential properties, marinas, shopping malls, sports facilities, and clubs. These will be open to both residents and tourists. More artificial islands, the World Islands, are now being constructed near the Palm Jumeirah. They consist of 300 private islands grouped into the shape of the continents of the world and will be used for estates, private homes, community islands, and resorts. Unquestionably, these artificial islands are one of the wonders of the modern world. They will also maintain Dubai's status as one of the leading tourist destinations in the region. What is the passage written for?
To introduce the wonderful artificial islands. To show how to build artificial islands. To offer a travel service for tourists. To prove the Palm Islands are the largest artificial islands in the world.