Final answer:
Cinco de Mayo, observed on May 5, is an event that celebrates Mexican heritage and victory over France. Additionally, Menstrual Hygiene Day on May 28 aims to raise awareness about menstruation and hygiene practices.
Step-by-step explanation:
One special observance event that is recognized every year during the month of May is Cinco de Mayo. This event, held on May 5th, commemorates the Mexican victory over the French Empire at the Battle of Puebla. It's a celebration of Mexican independence and heritage, particularly celebrated by Mexican Americans. Another significant event in May is Menstrual Hygiene Day, which takes place on May 28th. This day aims to break taboos around menstruation and promote good menstrual hygiene to prevent health problems and create awareness about the challenges faced regarding menstrual health in many countries.