During the summer and fall, thousands of Spaniards swarm the Catalonian city of Tarragona to climb on top of one another and form a human tower.

(David Oliete Casanova)

The human tower, or "castell" in Catalan, was originally the culminating point of rural 18th century Catalonian folk dances. But it became so popular that it inspired its own competitive event.

Today, people train to become castellers and join teams, which compete during the festival season from June until November. Though the technique of building a castell may appear random from the outside, each casteller has a specific position and function within the tower. And each team has its own construction methods. During competitions, music — a flute or a drum — is played and the melody changes as the castellers get higher and higher. When the top person, the "anxenta," reaches the peak, he or she has only a few seconds to salute the crowd and be crowned the winner. Teams also have to deconstruct without falling apart to win. So far, the highest human towers have extended 10 levels.

(David Oliete Casanova)

David Oliete Casanova, a photographer from Tarragona, grew up around these competitions. And in 2012, he photographed the Concurs de Castells competition from a unique vantage point. "I was taking these pictures from a circular platform located just at the center top of the arena. For security reasons, I was using a harness," Casanova said in an interview. "I was so thrilled to be able to be there and see that sort of image from above. You cannot only feel the voices, emotions, and colors from there, but you can see the behavior of all the team members. People are nervous, excited, and so focused on being able to build and dismantle their human towers successfully," he said.

Below, a look at castells in action from Casanova's awe-inspiring 2012 series.

(David Oliete Casanova)

(David Oliete Casanova)

(David Oliete Casanova)

(David Oliete Casanova)

(David Oliete Casanova)

(David Oliete Casanova)

(David Oliete Casanova)

(David Oliete Casanova)

(David Oliete Casanova)

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