Complex sentence: Wallis and Futuna, an overseas territory of France in Oceania has a rich Polynesian culture that is very similar to the cultures of its neighbouring nations Samoa and Tonga.
Split into simpler sentences: Wallis and Futuna, an overseas territory of France in Oceania has a rich culture. The culture of Wallis and Futuna is Polynesian, and is very similar to the cultures of its neighbouring nations Samoa and Tonga.