Here is a great series of photos taken by Frances Benjamin Johnston showing the New Willard shortly after it opened. Henry Janeway Hardenbergh designed the Beaux-Arts building, which went up in phases between 1901 and 1904 so the old hotel could keep operating while the new one rose around it.
Johnston’s photos turned out to be more important than anyone could have known. No blueprints or architectural drawings of the Willard’s interiors survived the hotel’s long decline, so when artisans restored the building in the 1980s, they used her photographs as the primary reference. The hotel reopened in August 1986.
Source: Library of Congress