Oahu Island is one of the eight major islands of Hawaii. It is the most populated, thus most developed islands of all Hawaii and is the center of business and tourism. The population of Oahu is very diverse providing a unique and friendly environment for anybody to enjoy a visit here.
As for activities, hiking around the island of Oahu is a lot of fun. Both locals and tourists enjoy hiking such places like Diamond Head, Kokohead, 3 Peaks, and the Pillbox. Everyone knows the world class waves in North Shore where professional surfers around the world come together to compete every winter. Of course, even you are not a professional surfer, anybody who enjoys beach culture can have a lot of fun all in the island's countless beautiful beaches.
If you are traveling there, you are most likely spending some time in Honolulu, namely Waikiki and Ala Moana where the majority of Hawaii's hotels and shopping centers are concentrated. Waikiki is on a flat land so it is easy for anybody to walk around and enjoy the tropical climate of Hawaii all year round.