Holy Saturday (Sábado Santo) is a Christian holiday in Mexico prior to Easter Sunday. Solemn vigils are held at churches on this day.

Holy Saturday (Latin: Sabbatum Sanctum) i.e. the Saturday of Holy Week, also known as the Great Sabbath, Black Saturday, or Easter Eve, and called “Joyous Saturday” or “the Saturday of Light” among the Copts, is the day after Good Friday. It is the day before Easter and the last day of Holy Week in which Christians prepare for Easter. It commemorates the day that Jesus Christ’s body lay in the tomb. https://en.wikipedia.org/wiki/Holy_Saturday

More information here: https://www.eventsloscabos.com/2013/04/holy-saturday-sabado-santo/