Difference between Christmas Eve, Christmas Day, Boxing Day - date

What is the difference between Christmas Eve, Christmas Day and Boxing Day ? At what date does each of them occur ?

In many countries:

• Christmas Eve - occurs on 24th December. It is a day for preparation. In some countries it is a national holiday.
• Christmas Day - occurs on 25th December. Main Christmas day. Presents are usually opened in the morning.
• Boxing Day - occurs on 26th December. Public holiday.