2 Puerto Rico Sites Now US Historic Landmarks Two Puerto Rican sites have been named U.S. historic landmarks: the colonial district of Old San Juan and the home of a poet and literary critic. Old San Juan is the oldest city of any U.S. state or jurisdiction. It is also the site of the oldest U.S. home, convent, governor's mansion and Christian church. It features brightly colored buildings and blue cobblestone streets. The other landmark is the San Juan home of Concha Melendez Ramirez, a prominent literary figure from the 20th century. She also was the first woman to become a member of the Puerto Rican Academy of the Spanish Language. Resident Commissioner Pedro Pierluisi said Wednesday that officials will now seek to have Old San Juan listed as a UNESCO World Heritage City.