A shimmering metallic wall slices through a scrubby mound on the edge of a highway in Philadelphia, like a long steel blade cutting into the earth. Halfway along its length, this silvery barrier flips up, recalling the lid of a giant laptop, forming an entrance canopy that beckons you inside. As you ascend the planted knoll, you find great furrows gouged into the ground, jagged concrete sinkholes from which the peaks of colourful sculptures protrude.
Welcome to Calder Gardens, an otherworldly place conceived by Swiss architects Herzog & de Meuron to celebrate the work of Philadelphia-born Alexander Calder, master of mobiles. It is one of the strangest cultural complexes to be built anywhere in recent years. On an unpromising site no larger than a football pitch, wedged between two highways, a beguiling sequence of spaces take visitors on a journey of discovery deep into the ground. It is part barn, part cave and part rolling meadow, compressing a whole universe of different gallery types into one compact encounter.
