NYTimes on visiting the Grand Canyon.

…It’s not just a trip out of the human realm, but into the deep geology of the earth. Layer upon layer of the planet’s crust is revealed, stratum by stratum: the Toroweap limestone, the Coconino sandstone, the Redwall limestone, the Tonto Group; the Vishnu schist deep down, close to two billion years old, nearly half the total age of the planet — the stuff that is under our very feet as we go about our lives is laid bare here. And in the silence and stillness, in the solitude of the canyon in winter, it’s all the more impressive….