Which item in the list is constructed differently from the other two?

We spent our days in St. Petersburg touring historic churches, magnificent art museums, and admiring ornate palaces.]]> We spent our days in St. Petersburg touring historic churches, visiting magnificent art museums, and admiring ornate palaces. Add a word or phrase from the answer bank to rewrite "magnificent art museums" to match the construction of the first and third items. Then submit it and say the sentence.

We spent our days in St. Petersburg touring historic churches, magnificent art museums, and admiring ornate palaces.]]>