Analysis of information sources in references of the Wikipedia article "Semana santa" in English language version.
From Wednesday onward, Judas secretly watched for a chance to turn Jesus over to the chief priests, and so many Christians labeled this day as "Spy Wednesday." In the same vein various cultures reflected the somber mood of this day by calling it "Black Wednesday" or "Wednesday of Shadows," which also corresponds to the liturgical rite of Tenebrae that is celebrated on this day.
Ash Wednesday and Good Friday are Fast Days, when the amount of food eaten is reduced.
Great Week (or Holy Week) is the most important part of the liturgical year for the Eastern Churches. It belongs to the moveable liturgical cycle and follows the Holy and Great Lenten period, beginning with Palm Sunday and ending on Great Saturday evening before the Divine Liturgy of the Resurrection (Pascha).
The Protestant Episcopal, Lutheran, and Reformed churches, as well as many Methodists, observe the day by fasting and special services.
Holy Week. The last week in LENT. It begins on PALM SUNDAY; the fourth day is called SPY WEDNESDAY; the fifth is MAUNDY THURSDAY or HOLY THURSDAY; the sixth is GOOD FRIDAY; and the last 'Holy Saturday', or the 'Great Sabbath'.
The last seven days of this period constitute Holy Week. The first day of Holy Week is Palm Sunday, the fourth day is Spy Wednesday, the fifth Maundy Thursday or Holy Thursday, the sixth Good Friday or Holy Friday, and the last Holy Saturday or the Great Sabbath in Eastern Rite traditions.
Many Christians are already familiar with the ancient, and now recently restored, liturgies of the Three Days: Maundy Thursday, Good Friday, and the great Easter Vigil service of light, readings, baptism, and communion. The worship resources published by the Evangelical Lutheran Church in America, the Episcopal Church, the United Methodist Church, the Presbyterian Church U.S.A. and the Catholic Church include nearly identical versions of these liturgies.
Presbyterians, Methodists, and Roman Catholics call this day Passion/Palm Sunday; the United Church of Christ calls it Palm/Passion Sunday; Lutherans and Episcopalians call it The Sunday of the Passion: Palm Sunday.
Sufficient bread and wine may be consecrated on this day for the Mass of the Presanctified on Good Friday. The Sacrament is then taken to an altar of repose where the faithful are asked to "watch and pray". The altar, symbol of Christ is stripped of its vesture and the building is left bare for the solemnity of Good Friday.
Good Friday was a largely celebrated day for Lutherans. The church bells did not ring, because Jesus was dead, and the altar at the church was draped in black.
The liturgical color is black-or no color if the paraments (altar cloths) have been stripped.
The Three-Hour (Tre-ore) service, an extra-liturgical (that is, outside the liturgical tradition) service, held to mark the hours of Christ's passion from noon until three in the afternoon, was instituted by the Jesuits on the occasion of the 1687 Peru earthquake. The service was introduced into the Church of England in the 1860s and was for a time widely observed in Anglican and Lutheran and some Catholic churches. A prominent feature was preaching on the "Seven Last Words" of Jesus from the cross, a conflation of the accounts in the four Gospels.
The Easter Vigil consists of four parts: the Service of Light, the service of Readings (the Word), the celebration of Baptism, and the celebration of the Lord's Supper.
It has not been popular in decades, and it would be misleading to call it a "best-kept secret" of the Catholic Church—it's celebrated by some mainline Anglican and Lutheran communities as well.
Finally, Maundy Thursday has from an early period been distinguished by the service of the Maundy, or Washing of the Feet, in memory of the preparation of Christ for the Last Supper, as also by the stripping and washing of the altars