Rick Owens + Birkenstock Rotterdam Metallic Leather and Rubber Sandals

'Functional fashion' is an industry term that's thrown around a lot, but it really applies to Rick Owens' collaboration with German footwear brand Birkenstock. Part of the duo's second capsule, these redone 'Rotterdam' sandals have straps made from sleek silver-coated leather and honeycomb-debossed rubber. Like the original design, they have contoured footbeds that evenly distribute weight.