The Guardian Life Annex is a rare example of the low-rise building in Manhattan shaped by the aesthetics of the 20th century European Modernism, often called the International style. It is an elegant piece of design, only four stories tall and faced with anodized aluminum panels and tinted glass. It it occupies a large site between East 17th Street and East 18th Street that originally adjoined the company’s 1911 Union Square headquarter.