In the ever-turning merry go round of fashion trends, few brands have weathered the test of time quite like Birkenstock, which is celebrating its 243rd year as the be-all and end-all comfort shoe that never seems to go out of style. The iconic slip-on has been a staple in fashion’s mainstream every decade—be it on the barefoot hippies of the '60s or the grungy flannel-wearing kids of the '90s.

Even luxury brands like Celine, Prada and Fendi made Birkenstock-inspired sandals in the aughts, a testament to its appeal to every rung of fashion’s hierarchy. Consider it the Hermès Kelly bag of shoes—rather than adapting to trends and new designs, its secret to success is its timelessness.

“The product works,” proclaims Oliver Reichert, Birkenstock’s chief executive, as to how they’ve secured a permanent spot in the sartorial zeitgeist. “We’re always talking about two things: quality, and function.”

The Birkenstock Box bei Andreas Murkudis in Berlin

Thomas Meyer/ OSTKREUZ

So it’s no surprise, then, that their most recent project incorporates both. Birkenstock worked with the architecture firm Gonzalez Haase, who designed the Balenciaga flagship in Paris and the Andreas Murkudis boutique in Berlin, to create three mobile pop-up stores, dubbed the Birkenstock Box, which will travel to retailers throughout Europe, Asia, and the U.S., over the next two years. The boxes will be stationed directly outside their major brick and mortar partner stores as extensions of the retail space.

“The idea was a bit progressive,” explains Pierre Jorge Gonzalez of the no frills, clean edged, cork-lined boxes which mimic the design and material of the shoes. The project launched over the summer with the European box at Murkudis’ boutique, and continued to 10 Corso Como in Milan, before traveling to Paris, and the double-decker U.S. box began its journey at Barneys New York on Friday with a party following Saturday during New York Fashion Week.

A sketch of the planned Birkenstock pop-up at Barneys New York.

Each retail partner will curate the box’s interior to their own aesthetic, mixing their designer wares with a limited edition Birkenstock shoe they specially co-designed to toast the collaboration. Barneys reimagined the classic Arizona style, lining it with blue and pink fur, whereas Andreas Murkudis opted for a deep alligator green to honor his collaboration.

“We dance together with our partners,” begins Reichert. “Give us your interpretation of Birkenstock and let’s do it.”