He had brought her to this place not to behold scientific marvels, but rather to create them. And that was exactly what Katherine had been doing.
-- Narrator (Chapter 7)

Importance: Peter had created a special lab for his sister, Katherine, to perform experiments in Noetic Science. This quote describes the first time he took Katherine to the Smithsonian Museum Support Center, which was full of historical artifacts and scientific marvels, to see her new lab.

America’s intended destiny has been lost to history.
-- Narrator (Chapter 20)

Importance: Langdon is aware that the true purpose of America is not what is taught in history books. America’s forefathers had intended to create a new Rome and a new intellectual era, complete with temples that featured Greek gods and goddesses. Peter Solomon, Langdon's mentor, believed America’s forefathers intended scientific knowledge to be the guiding force of the development of the country.

No need?’ Sato demanded. ‘Professor, we have...
-- Sato (Chapter 21)