Bulls and tomatoes may be the key ingredients in Spain's most famous festivals, but masks and bizarre outfits are the showpieces in dozens of smaller town celebrations, many dating back to medieval times.

These festivals, held in off-the-beaten path towns across central and northwestern Spain, most often coincide with festivities celebrating the advent of spring, mixing Carnival and bizarre pagan-like rituals with mock battles between good and evil.

In this April 1, 2017 picture, a man representing a wild bear runs through 'Zarramacos' ringing their cowbells in representation of the traditional carnival of La Vijanera de Silio during a gathering of different villages' carnival masks and charact… — In this April 1, 2017 picture, a man representing a wild bear runs through 'Zarramacos' ringing their cowbells in representation of the traditional carnival of La Vijanera de Silio during a gathering of different villages' carnival masks and characters, in Casavieja, Spain, Monday, April 3, 2017. These festivals, held across central and northwestern Spain, most often coincide with festivities celebrating the advent of spring, mixing Carnival and bizarre pagan-like rituals with mock battles between good and evil. (AP Photo/Daniel Ochoa de Olza)

Town residents don horned and maned masks, multicolored conical hats, sheepskins and cowbells and parade through the narrow streets of their villages. Other participants pose as bears, wolves or devil-like characters brandishing sticks as they run about to entertain spectators.

The festivals' origins are for the most part vague and their titles— such as the "Cucurrumachos" in Navalosa town or the "Zarramaches" in the village of Casavieja — are more often than not untranslatable.

Casavieja's festival takes place on St. Blaise's day, Feb. 3, and celebrates tales of how shepherds living in the nearby mountains came down to the village on that day to be paid and began dressing oddly to entertain children.

The La Vijanera parade, held on the first Sunday of the year in the northern town of Silio, is a colorful a Carnival-type pageant symbolizing the expulsion of evil spirits and stars characters known as "Trapajones," dressed up in costumes made of wood, moss or corn cobs.

And while the mask festivals may not attract the tens of thousands of party-goers like Pamplona's San Fermin bull-running fiesta or the Tomatina tomato battle, they are very popular and draw more tourists and media each year.

The towns also strive to promote the festivals to keep their cultural heritage alive. As part of this effort, each year one of the towns stages a special event to showcase a variety of the characters from the different festivals.

This year's event, celebrated April 1 in Casavieja, featured the comical hairy bear and "Trapajon" straw figures of "La Vijanera" festival and the "Harramacho," savage-looking characters from the "Cucurrumachos" fiesta.

In this April 1, 2017 picture, a man looks as 'Zarramacos' dong their cowbells in a representation of the traditional carnival of La Vijanera de Silio during a gathering of different villages' carnival masks and characters, in Casavieja, Spain, Mond… — In this April 1, 2017 picture, a man looks as 'Zarramacos' dong their cowbells in a representation of the traditional carnival of La Vijanera de Silio during a gathering of different villages' carnival masks and characters, in Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture, revelers from San Pedro Bernardo village wearing the traditional 'Machurrero' mask and outfit parade during a gathering of different villages' carnival masks and characters in the small village of Casavieja, Spain, Mon… — In this April 1, 2017 picture, revelers from San Pedro Bernardo village wearing the traditional 'Machurrero' mask and outfit parade during a gathering of different villages' carnival masks and characters in the small village of Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture, revelers from San Pedro Bernardo village wearing the traditional 'Machurrero' mask and outfit rest and eat after a parade during a gathering of different villages' carnival masks and characters in the small village of … — In this April 1, 2017 picture, revelers from San Pedro Bernardo village wearing the traditional 'Machurrero' mask and outfit rest and eat after a parade during a gathering of different villages' carnival masks and characters in the small village of Casavieja, Spain, Monday, April 3, 2017. These festivals, held across central and northwestern Spain, most often coincide with festivities celebrating the advent of spring, mixing Carnival and bizarre pagan-like rituals with mock battles between good and evil.(AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture, a reveler in a mask from the traditional La Vijanera de Silio carnival runs after picking a branch from a tree during a parade at a gathering of different villages' carnival masks and characters in the small village of… — In this April 1, 2017 picture, a reveler in a mask from the traditional La Vijanera de Silio carnival runs after picking a branch from a tree during a parade at a gathering of different villages' carnival masks and characters in the small village of Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture a family looks as 'Zarramacos' ring their cowbells in a representation of the traditional carnival of La Vijanera de Silio during a gathering of different villages' carnival masks and characters, in Casavieja, Spain, Mo… — In this April 1, 2017 picture a family looks as 'Zarramacos' ring their cowbells in a representation of the traditional carnival of La Vijanera de Silio during a gathering of different villages' carnival masks and characters, in Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture a man looks at his phone while he walks by a 'Trapajon' a character from the Vijanera of Silio traditional carnival representing a natural entity during a traditional Spanish mask gathering parade in the small village o… — In this April 1, 2017 picture a man looks at his phone while he walks by a 'Trapajon' a character from the Vijanera of Silio traditional carnival representing a natural entity during a traditional Spanish mask gathering parade in the small village of Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture revelers from San Pedro Bernardo village wearing the traditional 'Machurrero' mask and outfit rest after a parade during a gathering of different villages' carnival masks and characters in the small village of Casavieja… — In this April 1, 2017 picture revelers from San Pedro Bernardo village wearing the traditional 'Machurrero' mask and outfit rest after a parade during a gathering of different villages' carnival masks and characters in the small village of Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture revelers from Navalosa village wearing the traditional 'Cucurrumacho' mask and outfit rest after a parade during a gathering of different villages' carnival masks and characters in the small village of Casavieja, Spain,… — In this April 1, 2017 picture revelers from Navalosa village wearing the traditional 'Cucurrumacho' mask and outfit rest after a parade during a gathering of different villages' carnival masks and characters in the small village of Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture, a man takes off his sock after performing as a 'Zarramaco' a character that stains his face in black and rings cowbells in representation of the traditional carnival of La Vijanera de Silio during a gathering of differ… — In this April 1, 2017 picture, a man takes off his sock after performing as a 'Zarramaco' a character that stains his face in black and rings cowbells in representation of the traditional carnival of La Vijanera de Silio during a gathering of different villages' carnival masks and characters, in Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

In this April 1, 2017 picture, a man dressed as a 'Trapajon' and representing a natural entity walks in the village's gym used as a changing room after a traditional Spanish mask gathering in the small village of Casavieja, Spain, Monday, April 3, 2… — In this April 1, 2017 picture, a man dressed as a 'Trapajon' and representing a natural entity walks in the village's gym used as a changing room after a traditional Spanish mask gathering in the small village of Casavieja, Spain, Monday, April 3, 2017. (AP Photo/Daniel Ochoa de Olza)

Every spring they come from towns across central and northwestern Spain, clad in elaborate costumes — some as trees, others as bears, still others as monsters who could have emerged from some sort of fever dream.

First they attend local festivals, often timed to coincide with celebrations of spring. They parade through narrow streets in masks with horns and manes, multicolored conical hats, sheepskins and cowbells.

The festivals' origins are for the most part vague and their titles — such as the "Cucurrumachos" in Navalosa town or the "Zarramaches" in the village of Casavieja — more often than not untranslatable.

Then, they converge on one town, a different one each year, for a special event to showcase characters from the various festivals. The idea is to promote the festivals to help keep the towns' cultural heritage alive.

This year's event, celebrated April 1 in Casavieja, featured the comical hairy bear and "Trapajon" straw figures of "La Vijanera" festival and the "Harramacho," savage-looking characters from the "Cucurrumachos" fiesta.