May 16 is the 136th day of the year in the Gregorian calendar, with 229 days remaining until the end of the year. It is often associated with various historical events, celebrations, and observances around the world. On this day, several notable events have occurred, including the founding of the United States Postal Service in 1775 and the first successful human organ transplant in 1954. Additionally, May 16 is recognized as International Day of Living Together in Peace, promoting harmony and understanding among people.