Most of the houses in the neighborhood are stone foundations and wood construction, but the Triangle Historic District along Huntington Avenue is stone and brick, and one of only eight such districts in Boston given landmark status by the city. These seventy-one buildings bordered by Huntington Avenue, Tremont Street, and Worthington Street exemplify the development of the neighborhood from the 1870s through the 1910s. Construction of this area was begun in 1871. The Helvetia, a distinctive apartment hotel, was built at 706–708 Huntington Avenue in 1884–1885; a Georgian revival apartment building known as The Esther was built at 683 Huntington/142–148 Smith Street in 1912. Both buildings continue have retail on the ground floor and apartments above. Similar row houses line one side of Delle Avenue a few blocks away from the Triangle District. Taller and larger brick row houses also line Huntington Avenue, Wait Street, and South Huntington.