I thought it was yellow and made of dilapidated concrete, but Eero Saarinen's Gateway Arch, completed in 1965, is, in my opinion, one of the most important public modernist sculptures in America. Its stainless steel shell shines in the sun until it almost looks like a prism one can walk through to get out west.

Chloe was mobbed by fans in St Louis (seriously, a whole pack of feral middle-aged Midwestern men waited for us at the St. Louis airport with American Psycho stills for her to sign), so I mostly just pretended to be her bodyguard. But one man had his own claim to fame: this guy has collected issues of Vogue since the 1970s and decided, understandably, to turn his favorite covers into a sensible pair of pants.

At the Dada Ball, there was a fashion show of vintage designer dresses from Cameron Silver's Decades collection. Three models mysteriously dropped out at the last minute and so a few city visitors—like Fabiola Beracasa, shown here—filled in.

The guard didn't appreciate my cigarette break by the Richard Serra spiral in the back garden of the museum but, at twilight, it really did look like some archaic totem with a monolithic castle appearing in the distance.

Derek took a few hours off from celebrating contemporary art to do a hometown book reading of his new advice tome, Classy, at Left Bank Books. Many of his grade-school teachers, high-school classmates, and family were in attendance—one even asked how he managed to get to the top of the fashion world. The answer to that question is the subject of his next book.

On the last day of our trip, a resident art collector and interior designer Jimmy Jamieson opened his doors for us so we could see his works–like this Warhol portrait of Jamie Wyeth—and have lunch in his garden. His house is pure modernism in this gorgeous private drive of late 19th Century mansions.