Ascension is a Christian holiday. The word "ascension" means "going up". According to the story told in the Bible, Jesus ascended (went up) to heaven. This was seen by his apostles. The holiday is celebrated forty days after his resurrection. The story tells that Jesus' body went to heaven, and that in heaven he sits at the right-hand side of God the Father.
Ascension Day is officially celebrated on a Thursday. However, not all countries hold the feast on this day. It is one of the ecumenical feasts. All Christians celebrate this feast, much like Easter and Pentecost. It is a very important feast in the calendar of the Christian Church.
In some countries (at least in Austria, Belgium, Colombia, Denmark, Finland, France, Germany (since the 1930s), Haiti, Iceland, Indonesia, Liechtenstein, Luxembourg, Madagascar, Namibia, The Netherlands, Norway, Sweden, Switzerland and Vanuatu) it is a public holiday; Germany also holds its Father's day on the same date.