One of the reasons to visit Copley Square: It’s home to the Trinity Church, the 1877 building that’s one of H.H. Richardson’s most famous works, done in his signature Richardson Romanesque style. While here, stop in the Boston Public Library’s McKim Building, a National Historic Landmark that dates from 1895. Among its treasures are murals by John Singer Sargent and Edwin Austin Abbey and collections of rare books, manuscripts, maps and prints. When you’re done touring these two sites, spend some time people-watching before exploring the shops and restaurants in the area.