The oldest house on Capitol Hill, with parts dating back to 1680, Sewall-Belmont House has a fascinating history. Sections of the Louisiana Purchase were written here, and, roughly a century later, the amendment giving women the right to vote was drafted under its roof. In 1929, it was purchased by the National Women's Party, to serve as its headquarters. It is now a museum and library focusing on the advancement of women's political rights. Admission is free.