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

2) The blue whale is the largest animal to have ever existed, with an average length of about 82 feet (25 meters).

3) The ancient city of Athens, Greece, is often considered the birthplace of democracy, where citizens had a say in the decision-making process.

4) In Hindu mythology, the Bhagavad Gita is a sacred text that contains a conversation between Prince Arjuna and the god Krishna, who serves as his charioteer. It delves into philosophical and moral dilemmas and provides guidance on duty, righteousness, and the path to spiritual enlightenment.