Christian holidays are celebrated throughout the year by most denominations. The oldest and most important Christian holiday is Easter, a spring holiday that celebrates Jesus Christ's resurrection from the dead.
Saints' days are also important to most Christian denominations. Some of these, such as St. Patrick's Day and St. Valentine's Day, have come to play a prominent role in popular western culture. Other holidays with Christian origins that are now mostly secular celebrations include Mardi Gras and Thanksgiving.