Task: Explanation
Input (English): A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Of over 90,000 places listed on the country's National Register of Historic Places, only some 2,500 are recognized as National Historic Landmarks. Question: Which National Historic Landmark in Oberlin, Ohio was also home to the first African American that was elected to a United States Public Office?  Answer: John Mercer Langston House
Output (English): A National Historic Landmark NHL is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance.