From Torontoist:

“This year, a more cryptic stencil has appeared on the Humber Bay Arch Bridge, boldly proclaiming “ISBN 486-28495-6” for all to see and ponder. This International Standard Book Number turns out to be a paperback edition of Henry David Thoreau’s Walden; Or, Life in the Woods.

In Walden, Thoreau wrote, “A lake is the landscape’s most beautiful and expressive feature. It is earth’s eye; looking into which the beholder measures the depth of his own nature.”

Photo by Val Dodge.