In 1830, John Hollensbury's home was one of two homes directly bordering an alleyway which received an annoying amount of horse-drawn wagon traffic and loiterers. To prevent people from using the alleyway, Hollensbury constructed a 7-foot (2.1 m) wide, 25-foot (7.6 m) deep, 325-square-foot (30.2 m2), two-story home using the existing brick walls of the adjacent homes for the sides of the new home. The brick walls of the Hollensbury Spite House living room have gouges from wagon-wheel hubs, and the house is still standing and occupied.
There are two items of importance on the front of the house. The first is a cast-iron fire shield on the front, which signifies that a 19th-century owner paid the local fire company to ensure that it would respond if the house caught fire. The second is a plaque from the Historic Alexandria Foundation Early Buildings Survey. Be sure to check those out as you look for the cache (nanotechnology bison tube).
Be sure to cross the street to truly appreciate the width of the house compared to its neighbors.
The cache is a magnetic nano on the same block.