It was part of the Tarragona 2018 Cultural Festival called "Fires, Festivals I tradicion" - or Fairs, Festivals and Tradition.

The climbers who are known as "castellers" form human towers.

There can be few sporting events with a longer tradition. 

It is said to have begun in the region in the late 18th century. 

Each of the four teams at a special display in Placa de Font in Tarragona was known as a "colla".

"Each tower starts from small beginnings and goes up, maybe eight or ten rings, 12 metres high," said Francesc Olive Clermont, a casteller since he was five-years-old and still a regular participant at 71 with Colla Jove Xiguets de Tarragona.

"It is a little dangerous, but if there is a fall, usually it is just an injury to the arm."

One team member calls directions from below and each line-up is encouraged by a small group of musicians who play flutes and and "timbals" - small drums - during the climb.

The music they play is the "Toc de Castells".

"The music provides a rhythm for the climb, and it reaches a crescendo to announce that they have reached the summit," said Clermont.

A small child known as the "Anxenta", wearing a safety helmet, climbs to the top of the tower and waves in salute to signify that the castell is complete. 

It was the cue for thunderous applause from a large crowd that had gathered. 

Some watched from the many balconies around the square.

Each colla wore different colour shirts, embroidered with the local insignia, and many of the participants wore headscarves.

"Each team is like a family," said Clermont. 

"They are formed from young and old alike, men and women.''

None of the participants are paid, nor will they receive one of the specially minted Tarragona 2018 medals.

"It is not about the money, it is all heart," Clermont added.

Artistic and cultural festivals have been a part of the Olympic Movement since 1912.

There were also exhibitions and dramatic performances alongside the 1955 Mediterranean Games in Barcelona.

The festival here includes concerts, exhibitions and firework displays in each of the 15 satellite centres around the region.

In El Vendrell, the centre for handball, a costumed drama featured druids and priestesses from the Roman era, complete with seahorses. 

Other attractions include an exhibition on the legends of sport.