Niagara
In Chapter 13, Vincent Hemmingway finally comes to see Mary in London after she was been waiting. They were in a ways at a loss of words, so Mary asked him about his travels. He began talking about Niagara and says, ""Niagara," said Hemming, with a certain solemnity, "Niagara is something like London. The great falls, you know, are not beautiful; neither is London. But they are, like London, a unique, a terrifying spectacle. The roar, the immensity, the sense of a great power for ever driving forward; all these things are identical.