The third largest island of all Hawaiian islands, Oahu is generally known as the Gathering Place. It is basically a volcanic island with a total area of about 1545 sq. kms. and is located at an elevated height of about 4000 ft. above the ground level. With the location of a large number of beaches in the area, tourism is an important part of the local economic activity in the region. There are many places registered as the National Register of Historical Places. Some are also engaged with various type of trade and services in the region.