The most prominent feature of this controversial new future-primitive building, designed by Herzog & de Meuron, is the massive tower that emerges from the surrounding canopy of trees, making all those who approach from the 10th Avenue entrance to Golden Gate Park feel like the vanguard of an expedition that's just stumbled across an ancient lost city - or an abandoned mothership. Most people would agree that the design - seemingly a combination of extra-terrestrial metals wedded to sharp angles and organic forms found in ancient structures (like a surreal interpretation of the temples of Machu Picchu) - is at once overwhelming and electrifying. The exterior walls are all made from patterned copper designed to take on the colour of the surrounding greenery as they oxidise. While the jury is still out about the building's exterior, the quality of its contents is not in doubt. Along with its vast collections of American art from the 17th to 20th centuries, the museum showcases an extensive collection from New Guinea and the Oceania, as well as contemporary crafts and textiles. There's also an excellent store and café with outdoor seating areas. However, with commanding views over the park, the soaring observation tower is worth the trip alone. The courtyard, café, store, sculpture garden and tower can be entered without paying the admission fee.