An Independence Day is an annual event commemorating the anniversary of a nation's assumption of independent statehood, usually after ceasing to be a colony or part of another nation or state; more rarely after the end of a military occupation.

Most countries observe their respective independence days as a national holiday, and in some cases the observance date is controversial or contested. Not all countries observe an independence day holiday, choosing to celebrate other national days instead of or alongside an independence day.

Ohi Day (also spelled Ochi Day, Greek: Επέτειος του «'Οχι» Epeteios tou "'Ohi", Anniversary of the "No") is celebrated throughout Greece, Cyprus and the Greek communities around the world on October 28 each year, to commemorate Greek Prime Minister Ioannis Metaxas' (in power from August 4, 1936, until January 29, 1941) rejection of the ultimatum made by Italian dictator Benito Mussolini on October 28, 1940.

This ultimatum, which was presented to Metaxas by the Italian ambassador in Greece, Emanuele Grazzi, on October 28, 1940, at dawn (04:00 am), after a party in the German embassy in Athens, demanded that Greece allow Axis forces to enter Greek territory and occupy certain unspecified "strategic locations" or otherwise face war. It was allegedly answered with a single laconic word: όχι (No!) However, his actual reply was, Alors, c'est la guerre (Then it is war).

The Double Ninth Festival (Chung Yeung Festival in Hong Kong, Vietnamese: Tết Trùng Cửu), observed on the ninth day of the ninth month in the Chinese calendar, is a traditional Chinese holiday, mentioned in writing since before the East Han period (before AD 25).

According to the I Ching, nine is a yang number; the ninth day of the ninth lunar month (or double nine) has too much yang (a traditional Chinese spiritual concept) and is thus a potentially dangerous date. Hence, the day is also called "Double Yang Festival" (重陽節). To protect against danger, it is customary to climb a high mountain, drink chrysanthemum wine, and wear the zhuyu (茱萸) plant, Cornus officinalis. (Both chrysanthemum and zhuyu are considered to have cleansing qualities and are used on other occasions to air out houses and cure illnesses.) On this holiday some Chinese also visit the graves of their ancestors to pay their respects. People eat Chongyang Cake on the day.