From http://www.heurichhouse.org/history.htm:
The Heurich Mansion was built in 1892-1894, during Dupont Circle’s golden era as the city’s premier residential neighborhood, by German immigrant, American citizen, brewer, real estate magnate, and philanthropist, Christian Heurich.
Nicknamed "The Brewmaster’s Castle" while Heurich lived there, it was the city’s first fireproof home, having been built of reinforced steel and poured concrete, a novel construction technique at the time, and unheard of for residential construction. To ensure its safety, none of the fireplaces were ever used, and the top of the tower features a salamander, in mythology, a creature that guards against fire.
A distinguished example of Richardsonian Romanesque architecture, this Category Two Landmark on the National Register of Historic Places enjoys an international reputation as the most intact late-Victorian home in the country, and has been featured on A&E’s "America’s Castles" and HGTV’s "Dream Builders."