Honolulu is the capital city of the State of Hawaii and located on the island of Oahu which is also famous for Waikiki and Pearl Harbor. The below link website is the official tourism link for Oahu and it is well done with sublinks for things to do.
Welcome to Oahu
Waikiki is famous for its beach breaks, making it a popular haven for surfers. It is no wonder that the statue of Duke Kahanamoku, the person credited for making surfing popular as a modern sport, is among the most visited and photographed landmarks in Waikiki.
At the Pearl Harbor National Memorial, learn about one of the most pivotal moments in US history: the attack on Pearl Harbor, and the subsequent entry of the United States into World War II.
Hanauma is one of the most popular tourist destinations on the Island and has suffered somewhat from overuse. At one time, this popular tourist destination accommodated over three million visitors per year. Hanauma is both a Nature Preserve and a Marine Life Conservation District. Reflecting changes in attitude, its name has changed over time from Hanauma Bay Beach Park to Hanauma Bay Nature Preserve.
Diamond Head is a volcanic tuff cone on the Hawaiian island of Oʻahu and known to Hawaiians as Lēʻahi. The Hawaiian name is most likely derived from lae plus ʻahi because the shape of the ridgeline resembles the shape of a tuna’s dorsal fin.