Metropol Parasol is a wooden structure located at La Encarnación square, in the old quarter of Seville, Spain. It was designed by the German architect Jürgen Mayer-Hermann and completed in April 2011. It has dimensions of 150 by 70 metres (490 by 230 ft) and an approximate height of 26 metres (85 ft) and claims to be the largest wooden structure in the world. Its appearance, location, and delays and cost overruns in construction resulted in much public controversy. The building is popularly known as Las Setas de la Encarnación (Incarnación's mushrooms).
Construction began on June 26, 2005, with an estimated cost of 50 million euros and a projected completion date in June of 2007. However, unknown to the public, the project soon faced difficulties. By May 2007 engineering firm Arup informed the municipal authorities that the structure was technically infeasible as designed, given that a number of structural assumptions had not been tested and appeared to violate the limitations of known materials. Much time was spent developing a feasible alternative plans to buttress the structure, which themselves proved impractical because of the added weight. A feasible design using glue as reinforcement was finally settled on only at the beginning of 2009. Due to delays, the by some estimates the total cost of the structure approached 100 million euros.