Réveillon is a traditional celebration that occurs on the night of December 31st, marking the transition from the old year to the new one. It is especially popular in countries like France, Brazil, and Portugal. The festivities often include a large feast, family gatherings, and various cultural customs, such as fireworks and music. In France, Réveillon typically features a lavish dinner that may include dishes like foie gras and oysters. In Brazil, people often wear white for good luck and celebrate on the beach with fireworks and parties. Overall, Réveillon is a time for joy, reflection, and hope for the coming year.