In Korean culture, the hwan gap is a person's 60th birthday party. You are supposed to throw a huge party and invite everyone you know; it is a way to display wealth, success, and generosity.
In the main ceremony of the hwan gap, the birthday person and their spouse sit behind a long table covered with food. Their children, one by one, go up and bow low before them, and respectfully offer them a cup of wine. The food on the table is just for show, and is usually rented -- huge stacks of decorated rice cakes and pyramids of oranges are popular.
Ideally, one would also hold one's grandchildren in one's lap as part of the proud display of success in life. Unfortunately they don't rent out grandchildren like they do the big stacks of painted rice cakes.
The hwan gap marks the end of a cycle of a person's life, and the beginning of a new cycle.