Teams of up to 500 men, women and children compete to build the tallest tower - which can be as many as ten levels tall.The tradition in the Catalonia region dates back to the end of the 18th century, and the formations are known as 'castells'.Each team carefully builds the tower, with their strong and heavy members forming its base while the lightest making a dangerous ascent to the top.The Human Tower Competition - known in Spain as the 'Concurs de Castells' - takes place in the city of Tarragona, 60 miles south-west of Barcelona.More than 20,000 people come to watch the participants, with points awarded to teams depending on the difficultly and height of each castell.The teams have five rounds to build their best towers - and their final score comes from the total points gained for their best three attempts.(dailymail.co.uk)Bakudaily.az