An undiscovered treasure on Manhattan's tony Upper East Side, Carl Schurz Park is unknown to all but a few locals. Of the hundreds of writings on the parks of New York City, none to date covers this small gem of a park, with its utterly unique features: a working river runs by it, Gracie Mansion adorns its upper point, and history is written into each of its 15 acres.

A book of days, "perpetual calendar" or "birthday book," lets you keep track of annually recurring events or personally memorable occasions.

Accurate for decades to come.