Belgian workers brushed aside rain and laid down 700,000 begonias on Friday (August 11) in a biennial celebration that transformed its ancient Grand Place into a huge carpet of flowers. The flower carpet recalls Belgian's tapestries and rugs of centuries past, which hang in castles and museums across Europe. Each show takes two years to plan, with the first year devoted to design and the second to preparing the flowers. "These begonias were planted in the summer of 2005 just for this show," said Pieter Moens, a spokesman for the coalition that put on the show. "They were cut from the fields near Ghent starting at 4 a.m. and arrived in Brussels in the afternoon." More than 120 volunteers carefully arranged the flowers - 10 main colours and a sprinkling of mixed-colour flowers - on specially marked plastic set over the cobblestones of the square, interspersed with green turf. The yellow, purple, red, orange and other coloured flowers were arranged to form a huge symmetric pattern that evoked the middle ages, as rain intermittently dripped. For example, some patterns were based on insignia used by alchemists. "They use begonias because they are 98 percent water and can withstand heat and withstand rain," the spokesman said. Belgium is the world's largest producer of begonia tubers, with four out of five of the 80 million produced sent to the Netherlands, France, the United States among other countries. By evening the skies had cleared and the 77 by 24 metre (250 by 80 feet) carpet was formally inaugurated with a light show and fireworks. The carpet has 300 flowers per square metre (28 per square foot).