“We used to build civilizations. Now we build shopping malls.”

“Because we humans are big and clever enough to produce and utilize antibiotics and disinfectants, it is easy to convince ourselves that we have banished bacteria to the fringes of existence. Don't you believe it. Bacteria may not build cities or have interesting social lives, but they will be here when the Sun explodes. This is their planet, and we are on it only because they allow us to be.”

“Every twenty minutes on the Appalachian Trail, Katz and I walked farther than the average American walks in a week. For 93 percent of all trips outside the home, for whatever distance or whatever purpose, Americans now get in a car. On average, the total walking of an American these days - that's walking of all types: from car to office, from office to car, around the supermarket and shopping malls - adds up to 1.4 miles a week...That's ridiculous.”

“Nothing - really, absolutely nothing - says more about Victorian Britain and its capacity for brilliance than that the century's most daring and iconic building was entrusted to a gardener.”

“In office buildings and retail premises in which entry is through double doors and one of those doors is locked for no reason, the door must bear a large sign saying: “This Door Is Locked for No Reason.”

“To tell you the truth, I'm amazed we've come this far," he said, and I agreed. We had hiked 500 miles, a million and a quarter steps, since setting off from Amicalola. We had grounds to be proud. We were real hikers now. We had shit in the woods and slept with bears. We had become, we would forever be, mountain men.”

“We are so used to the notion of our own inevitability as life’s dominant species that it is hard to grasp that we are here only because of timely extraterrestrial bangs and other random flukes. The one thing we have in common with all other living things is that for nearly four billion years our ancestors have managed to slip through a series of closing doors every time we needed them to.”