Hangul are the Korean characters created and spread throughout Korea beginning in 1446 by King Sejong of the Joseon dynasty. Even back then, Korean was spoken in Korea like it is today, but since Korean had no characters of its own, they used Chinese characters when writing. However, Chinese characters took so long to learn that farmers and other people who had to work had a hard time learning them. So King Sejong, in order to create a writing system that anyone could learn, founded a place called Jiphyeonjeon where Hangul was created.
한글날에는 전국 여기저기에서 다양한 행사들이 열립니다. (hangeullareneun jeonguk yeogijeogieseo dayanghan haengsadeuri yeollimnida.): Various events take place all over Korea on Hangul Proclamation Day.
P.S. Get Your Daily Dose of Korean with 1-Minute Mini-Lessons
The Daily Dose of Korean is a Calendar that gives you new, 1-minute lessons every day. Why? Because learning a little every day is easy, strengthens your habits and motivation and you improve your Korean over time. Lessons range from culture and holidays to grammar, slang, phrases and more. Find it in the Korean Resources menu or in the Quick Links menu on your Dashboard.