Late last August, Nancy and I were in Boston. As we usually do when we are there, we took a long walk at what is called the Concord Unit of the Great Meadows National Wildlife Refuge. It is a large pond or wet meadow, near the Revolutionary War town of Concord, that is ringed by forest, much taken-over at the moment by lotus plants, and frequented by geese, egrets, herons and dragonflies. Only a few lotus flowers remained, most having shed their white petals to expose conical seedpods of extraterrestrial appearance. Bees hurried among the purple loosestrife, and crumbling cattails disgorged their fluff in vain expectation of a breeze. Warm, humid, silent, alive — the Concord Unit gives a strong feeling of place: All of your senses tell you in chorus that you are there.