With their tall conical hats, monkish robes and facial hoods that only show their eyes, the so-called "nazarenos," or penitents, in Spain's immensely popular Easter processions cut an eerie, and stunning, look as they parade solemnly in silence, or to the beat of drums and wailing bugles.

While no longer the bastion of Roman Catholicism it once was, Spain has lost none of its fervor for religious celebrations, and Easter week is a spectacular example.

For days leading up to Easter Sunday each year, hundreds of colorful processions featuring penitents and magnificently decorated and sculpted religious floats, take place through streets of villages and cities, celebrating the Passion of Christ from the crucifixion to resurrection. The parades, particularly those in Seville and other Andalusian cities, have become major tourist attractions and are televised nationally.

In this Thursday, April 13, 2017 photo, hooded penitents from "La Oracion en el Huerto" brotherhood stand by the San Lorenzo church before taking part in a traditional annual Holy Week procession in Segovia, Spain. (AP Photo/Francisco Seco)

The processions vary greatly depending on the region but common elements are the hooded penitents, some carrying crosses or candles. The hats, which remind some of Klu Klux Klan costumes, are said to date back to the Spanish Inquisition when prisoners were made to wear them in public as a form of humiliation. The faces are covered so as to allow the penitent sinners to hide their identities.

In some processions, the penitents dress as Roman soldiers. In La Rioja region, many wear ankle chains and flagellate themselves while in northeastern Aragon, nazarenos draw their own on beating bass drums for hours on end.

Women traditionally form the backline of the processions, playing the role of mourners but dressed in stylish black dresses and high-heels, elaborately embroidered veils and intricately designed hair combs.

Some of the processions date back hundreds of years and their sculpted tableaux figures of Jesus and the Virgin Mary are considered much appreciated works of art.

The floats are extremely heavy and are carted by 10 or more so-called "costaleros," normally strong young men who wear protective corsets to avoid injury.

The processions are staged by brotherhoods, or clubs, whose members come from all walks of life and which nowadays often have no religious purpose beyond the processions.