Human towers on the National Mall in Washington

An amazed audience enjoyed yesterday in Washington one of Catalonia's most unique and beautiful traditions: Human towers.

Almost 400 members of the Colla Vella and Colla Joves dels Xiquets de Valls, longtime rivals from the Catalan town where the tradition started, build towers of up to seven levels.

The performance was part of the Smithsonian Folk Festival, that this year features Catalonia's culture.

If you missed their performance on Friday, you still got time to check this unique tradition during the weekend.

On Saturday, both teams will compete at 2pm in front of the Rinzler Stage. Colla Vella will perform again at the Plaça Major area at 4pm, all Washington local time.

On Sunday, Colla Vella will perform at 1pm at Plaça Major and 4 pm in front of the Rinzler Stage and Colla Joves at 2pm in front of the Rinzler Stage and 3pm in the Plaça Major. Every performance will last about one hour.

The Catalan tradition of making human towers is a celebration of teamwork and social cooperation. It is also extremely popular, with scores of castellers teams competing all year all over Catalonia, and involving thousands of people of both genders and all ages, from small children to full-grown adults.