Rangiroa is not a city, but an atoll in the Tuamotu Archipelago in French Polynesia. It is the largest atoll in French Polynesia and one of the largest in the world. The main town and administrative center of Rangiroa is called Avatoru. It is located on the northern end of the atoll and is home to most of the local population. Rangiroa is known for its stunning coral reefs, crystal-clear lagoons, and vibrant marine life, making it a popular destination for diving and snorkeling enthusiasts.