Cúpula del Milenio, Multi-purpose dome in Plaza del Milenio, Valladolid, Spain

The Cúpula del Milenio is a multipurpose dome with a metallic framework spanning 45 meters across its widest point. Its exterior features polygonal sections covered in triple-layer ETFE material that manages internal temperature and light while allowing visibility from outside.

The dome was first installed for Expo Zaragoza 2008, where it served as the SED Pavilion. Valladolid's city council acquired it and had it rebuilt on the Plaza del Milenio; it opened to the public in May 2011. The move and assembly cost 16 million euros, a sum that drew criticism, as did its design, seen as breaking with the city's architecture. It was part of a Spanish pilot project testing a city model against climate change.

The dome serves as a flexible entertainment venue where visitors experience tennis matches, basketball games, circus acts, theater productions, concerts, and exhibitions under one roof. It has become a gathering place where locals and tourists enjoy diverse cultural events throughout the year.

The venue features an underground parking area and bicycle lanes for easy access, with seating capacity for around 1,250 visitors. Inside and around the grounds you will find a restaurant, children's playground, and adventure park to explore during your visit.

The ETFE skin captures 90% of sunlight but emits only 80%, so the dome lights and cools itself naturally; three layers, one with aluminium microparticles, reflect solar heat. The floor is a jointless chemical composite, not stone, that expands and contracts with the walls.