Yesterday saw the unveiling of Richard Chai's temporary rotating pop-up shop, the Cave, as the fourth installation in Building Fashion's series of five collaborative projects. The designer paired with Daniel Arsham and Alex Mustonen of Snarkitecture, an arts-meets-architecture avant-garde group, who carved out the chasmal space from an existing foam structure beneath the New York City High Line—thrifty! The store opens with a celebration hosted by The Last Magazine and will be open to the public through October 31st, noon to six p.m. Visitors will get a glacial "we're-not-in-New-York-anymore" experience as they peruse Chai's men's and women's collections displayed in irregularly shaped crevices and cut-outs and in the cavernous environment. Check out this transient icy-hot spot while it lasts at 504 West 24th Street, and get excited for the final installation featuring conceptual designer Siki Im, opening November 5th.