Circa 1896: The Cosmopolitan is the hidden gem of St. Louis. Built in the heart of historic downtown for National Cash Register and later housing Clark Peeper Furniture (whose ghost sign still haunts the West wall), this high-class low-rise has most recently been the showroom, studio, and playground of design firm Antique Architectural Decor. The first-floor lounge and reception area is Gothic, with distinctive frescoes and house-made tile and glasswork. Looking out over the entrance is the mezzanine, featuring an incredible wood faux mural in the conference space. The brass elevator leads up to the third-level loft apartment, styled from the columns to the lighting design to be both contemporary and timeless. The crown jewel of The Cosmopolitan is the Gothic 5th-floor penthouse. Travertine floors, custom stone and tilework, illuminated stained glass, ceiling buttresses, and such modern amenities as Viking appliances and a home theater make it a space like no other. Obsessively detailed and utterly unique, this St. Louis treasure is not to be missed.