1) The first sound film, "The Jazz Singer," was released in 1927 and marked the transition from silent movies to "talkies."

2) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.

3) The first car with air conditioning was released in 1939.

4) In Chinese mythology, the Dragon Boat Festival (also known as Duanwu Festival) is celebrated to honor Qu Yuan, a poet and statesman of ancient China. It involves dragon boat races, eating sticky rice dumplings (zongzi), and performing rituals to ward off evil spirits and protect against diseases.